Due to its inland continental location and wide range of topography, Colorado’s climate is varied. Major geographic features include the High Plains in the east, the high mesas and canyons in the far west, and the Rocky Mountains in the central part of the state. Colorado has 58 mountain peaks higher than 14,000 feet, and it has the highest average elevation of any US state, at 6,800 feet. Due to Colorado’s semiarid climate and changes in elevation across the state, temperatures vary widely from day to night and over short distances. Typical low temperatures in the winter range from less than 0°F in several mountain valleys to more than 20°F in high desert regions along the western slopes, as well as lower-elevation locations in the south and east (1991–2020 averages). Summer high temperatures range from the mid-60s at high elevations to more than 90°F in far southeastern and western high desert regions. Annual precipitation varies widely across the state, from less than 8 inches in the middle of the San Luis Valley to more than 50 inches in some mountain locations. Seasonal patterns also vary. In the eastern plains and valleys, most precipitation falls during spring and summer, but the mountain peaks receive the most precipitation during the winter months.
Time series of observed and projected temperature change (in degrees Fahrenheit) for Colorado from 1900 to 2100 as described in the caption.
Y-axis values range from negative 4 to positive 20 degrees. Observed annual temperatures from 1900 to 2024 show variability and range from negative 2.6 to positive 3.9 degrees. By the end of the century, projected increases in temperature range from 1.9 to 7.3 degrees under the lower emissions pathway, from 4.4 to 11.2 degrees under the intermediate pathway, and from 8.9 to 18.5 degrees under the higher pathway.
Annual average temperatures in Colorado have increased more than 2.5°F since the beginning of the 20th century (Figure 1) and have remained consistently higher than the long-term average (1895–2024) since 1998. The hottest year on record was 2012, with an average temperature of 48.3°F, which was 3.4°F above the long-term average. Since the early 2000s, the state has experienced some of the highest spring and summer average temperatures in the historical record (Figures 2a and 2b). A new state record for maximum temperature (115.0°F) was set at John Martin Dam on July 20, 2019. In addition to the overall trend of higher average temperatures, the number of very hot days has mostly been above average since the early 2000s (Figure 3a). Colorado rarely experiences high nighttime temperatures due to its high elevation and generally dry climate, but the number of warm nights has mostly been near or above average since the early 2000s, with the 5-year average for the 2020–2024 period exceeding those of the 1930s (Figure 3b). The number of very cold nights has generally been near or below average since the 1980s (Figure 4).
Two graphs of the observed (a) spring and (b) summer average temperatures for Colorado from 1895 to 2024 as described in the caption.
Panel A: Spring Average Temperature
Y-axis values range from 36 to 50 degrees Fahrenheit. Annual values show year-to-year variability and range from 37.1 to 48.5 degrees. Five-year values also show variability and are all near or below the long-term average of 43.0 degrees between 1895 and 1984 but are all near or above average since 1985. The 1920 to 1924 period has the lowest 5-year value at 40.6 degrees, and the 2000 to 2004 period has the highest at 45.6 degrees.
Panel B: Summer Average Temperature
Y-axis values range from 60 to 70 degrees Fahrenheit. Annual values show year-to-year variability and range from 61.0 to 68.7 degrees. Five-year values also show variability and are all below the long-term average of 64.9 degrees between 1895 and 1929, above average between 1930 and 1939, and mostly near or below average between 1940 and 1999. An upward trend is evident since the late 1960s. Since 2000, 5-year values are all above average. The 1905 to 1909 period has the lowest 5-year value at 63.2 degrees, and the 2020 to 2024 period has the highest at 67.3 degrees.
Two graphs of the observed annual number of (a) very hot days and (b) warm nights for Colorado from 1900 to 2024 as described in the caption.
Panel A: Very Hot Days
Y-axis values range from 0 to 32 days. Annual values show year-to-year variability and range from 3.1 to 28.4 days. Five-year values also show variability and are all below the long-term average of 15 days between 1900 and 1929, above average between 1930 and 1939, and mostly near or below average between 1940 and 1999. Since 2000, 5-year values are all above average. The 1920 to 1924 period has the lowest 5-year value at 9.4 days, and the 2000 to 2004 period and 2020 to 2024 periods have the highest at 23.0 and 21.6 days, respectively.
Panel B: Warm NightsY-axis values range from 0 to 4 nights. Annual values show year-to-year variability and range from 0 to 3.3 nights. Five-year values also show variability and are all below the long-term average of 0.8 nights between 1900 and 1929, above average between 1930 and 1939, and mostly near or below average between 1940 and 1999. Since 2000, 5-year values are all near or above average. The 1945 to 1949 period has the lowest 5-year value at 0.3 nights, and the 2020 to 2024 period has the highest at 1.6 nights.
Graph of the observed annual number of very cold nights for Colorado from 1900 to 2024 as described in the caption.
Y-axis values range from 4 to 36 nights. Annual values show year-to-year variability and range from 6.4 to 31.9 nights. Five-year values also show variability and are below the long-term average of 18.3 nights between 1900 and 1909, all near or above average between 1910 and 1979, and all below average since 1980. The 2015 to 2019 period has the lowest 5-year value at 13.0 nights, and the 1915 to 1919 period has the highest at 26.7 nights.
Statewide total annual precipitation is 18.0 inches on average but has ranged from a low of 11.9 inches in 2002 to a high of 25.5 inches in 1941 (Figure 5). Statewide seasonal total precipitation has been variable. With the exception of the 2015–2019 period, Colorado has generally experienced below-average spring precipitation since the early 2000s (Figure 6a). Fall precipitation was generally above average from the 1980s through 2014 but mostly below average since then (Figure 6b). Snowfall totals also vary across the state, with the high mountains receiving 150 inches to more than 400 inches per year. Occasional blizzards can have significant impacts. In March 2019, a bomb cyclone (a storm system that rapidly intensifies) produced widespread blizzard conditions and record-high wind gusts and caused avalanches and major travel disruptions. This storm also set a state record for lowest atmospheric sea level pressure (970.4 hPa) on March 13 in Lamar. A widespread snowstorm from November 4–10, 2024 produced remarkable snow totals for many areas, including up to 60 inches of snow in the Sangre de Cristo Mountains and 24–36 inches across the southeastern plains—a rare occurrence for low-elevation regions. The storm produced the second-highest snowfall total for eastern Colorado, behind the historic blizzard of 1946.
Graph of the observed total annual precipitation for Colorado from 1895 to 2024 as described in the caption.
Y-axis values range from 10 to 28 inches. Annual values show year-to-year variability and range from 11.8 to 25.5 inches. Five-year values also show variability and are near or below average between 1895 and 1904, all near or above average between 1905 and 1929, mostly below average between 1950 and 1979, and all near or above average between 1985 and 1999. Since 2000, 5-year values are mostly near or below average. The 1930 to 1934 period has the lowest 5-year value at 15.8 inches, and the 1995 to 1999 period has the highest at 20.5 inches.
Two graphs of the observed total (a) spring and (b) fall precipitation for Colorado from 1895 to 2024 as described in the caption.
Panel A: Total Spring Precipitation
Y-axis values range from 0 to 10 inches. Annual values show year-to-year variability and range from 2.0 to 9.6 inches. Five-year values also show variability and are mostly near or above the long-term average of 5.3 inches between 1895 and 1959, all below average between 1960 and 1974, and mostly near or above average between 1975 and 1999. Since 2000, 5-year values are all below average except for the 2015 to 2019 period. The 1965 to 1969 period has the lowest 5-year value at 4.3 inches, and the 1940 to 1944 period has the highest at 6.8 inches.
Panel B: Total Fall Precipitation
Y-axis values range from 1 to 8 inches. Annual values show year-to-year variability and range from 1.5 to 7.3 inches. Five-year values also show variability and are mostly near or below the long-term average of 3.8 inches between 1895 and 1979 with a few exceptions, including the 1970 to 1974 period, with the highest 5-year value at 4.7 inches. Between 1980 and 2014, 5-year values are all near or above average, but they are below average since 2015. The 1900 to 1904 period has the lowest 5-year value at 2.7 inches.
Thunderstorms are common in the eastern plains and eastern mountain slopes, with the more intense storms bringing damaging hail and occasional flash floods. The mountains are effective thunderstorm generators, especially during the summer months, when humidity is highest. Northeastern Colorado lies in Hail Alley, the most hail-prone area in the entire country, with an average of 7 to 9 hail days per year. One of the most damaging hailstorms occurred on May 8, 2017, in Denver and surrounding communities. Hail size exceeded 2 inches in some places, damaging homes, businesses, and more than 100,000 vehicles. This was the costliest hailstorm in Colorado history, with insured losses exceeding $2 billion. On August 13, 2019, a hailstone that fell 8 miles northwest of Bethune set state records for hail weight (8.5 ounces), circumference (12.9 inches), and volume (16.6 cubic inches). A hailstone that fell near Kirk set the record for largest diameter (5.3 inches) on August 8, 2023. Locally intense thunderstorms can also cause flash flooding, particularly in the lower foothills east of the mountains. Unlike many areas of the United States, Colorado and other southwestern states have not experienced an upward trend in the frequency of extreme precipitation events (Figure 7). However, these events can be devastating when they do occur. During September 10–16, 2013, heavy rainfall from a nearly stationary weather system caused extensive river flooding across the foothills and the Front Range, some of the worst in state history. More than 15 inches of rain fell in some locations, and the storm caused more than $1.5 billion in damages. A new state record for 24-hour precipitation (11.9 inches) was set on September 12 at the US Geological Survey Rod and Gun station at Fort Carson.
Graph of the observed annual number of 1-inch precipitation events for Colorado from 1900 to 2024.
Y-axis values range from 0.5 to 4.0 events. Annual values show year-to-year variability and range from 0.6 to 3.4 events. Five-year values also show variability and are all near or above the long-term average of 1.8 events between 1900 and 1929 but are mostly near or below average since 1930. The 1950 to 1954 period has the lowest 5-year value at 1.3 events, and the 1905 to 1909 and 1995 to 1999 periods have the highest at 2.3 events each.
Since Colorado is a headwaters state, changes in precipitation can impact an area much larger than just the state itself. Four major US rivers have their source in Colorado: the Colorado, the Rio Grande, the Arkansas, and the Platte. Yearly variations in snowpack depths have implications for water availability across the West and the Great Plains, as snowmelt from the winter snowpack feeds many rivers and streams. For example, low snowpack levels in 2012 and 2018 resulted in low spring runoff across the southern Rockies. Following several warm and dry spells throughout the 2024–25 winter, spring 2025 saw the fourth-lowest snowpack totals in the last 40 years, with only 6 (out of 28) ski areas receiving more than 300 inches of snow, the amount needed for ideal ski conditions throughout the season. However, in years with heavy snow cover, a combination of snowmelt and widespread spring rains has the potential to cause spring flooding. Overall, there have been declines in snowpack throughout the western United States. In Colorado, there have been slight declines in snow water equivalent (SWE) for northern Colorado (Figure 8). Southern Colorado has seen larger declines, where the average April 1 SWE has been 13.3 inches since 2000 (compared to 16.3 inches for 1937–1999).
Line graph of the annual variations in the April 1 snow water equivalent (SWE) averaged over northern Colorado (top) and southern Colorado (bottom) from 1937 to 2024 as described in the caption.
Top: Northern Colorado
Y-axis values range from 0 to 30 inches. Annual values show year-to-year variability and are all between 5 and 20 inches across the entire period. Annual values range from a low of 5.6 inches in 2012 to a high of 19.5 inches in 1952.
Bottom: Southern Colorado
Y-axis values range from 0 to 30 inches. Annual values show year-to-year variability and are mostly between 10 and 25 inches between 1937 and 1977 but are mostly between 5 and 20 inches since 1977. Annual values range from a low of 5.0 inches in 1977 to a high of 29.7 inches in 1952.
Droughts are a natural part of Colorado’s climate (Figure 9). Colorado has been in drought almost constantly since 2001, with three historic droughts occurring in the past 20 years, beginning in 2002, 2012, and 2018. Three of the five driest years on record for Colorado have occurred since 2002. Drought conditions can increase the risk of wildfire. During the summer and fall of 2020, Colorado had one of its worst wildfire seasons, when warm and extremely dry conditions, combined with high winds and low relative humidity, led to the ignition and spread of numerous wildfires. Three of these grew to become the largest wildfires ever recorded in Colorado—the Cameron Peak Fire, the East Troublesome Fire, and the Pine Gulch Fire, which collectively burned more than a half million acres. Other western states had record-breaking wildfire seasons in 2020, and collectively, these fires cost more than $16 billion in damages, and the smoke created unhealthy air quality conditions for millions of people.
Time series of the Colorado Palmer Drought Severity Index for the years 1000 to 2024 as described in the caption.
Y-axis values are divided into dry and wet categories, ranging from 0 to negative 8 (dry) and 0 to positive 8 (wet). Annual values show variability and range from negative 7.5 to positive 5.3. Values for most years fall between negative 3 and positive 2, but values reaching negative 4 and positive 3 are common. The 20-year running average also shows variability, with values ranging from negative 2.1 to positive 1.7. Since the beginning of the modern era (red line), the running average is generally high in the positive range until the 1930s, then fluctuates above and below 0 until the 1990s. Since then, the running average shows a downward trend, reaching a low of negative 1.0 in 2014.
Under the intermediate and higher emissions pathways, historically unprecedented warming is projected during this century (Figure 1). Even under the lower emissions pathway, most projections show annual average temperatures exceeding historical levels by the middle of the century. However, projections for all three pathways show a large range of potential temperature increases, and some projections for the lower pathway are comparable to recent observed values. Increases in heat wave intensity are projected, but the intensity of cold waves is projected to decrease, continuing recent trends (Figure 4).
Under the intermediate emissions pathway, projected increases in total spring precipitation and winter precipitation (Figure 10) by midcentury are statistically significant for northern portions of the state but are less certain elsewhere. There is uncertainty in projections for annual, summer, and fall precipitation. Although heavier winter precipitation could provide important water for the water-scarce Southwest, rising temperatures are expected to raise the snow line (the average lowest elevation at which snow falls) and increase the likelihood that precipitation falls as rain instead of snow. This would reduce water storage in the snowpack, particularly at those lower mountain elevations that are now on the margins of reliable snowpack accumulation. Higher temperatures are also expected to result in an earlier melting of the snowpack, earlier peak runoff, increased evaporation rates, and decreased soil moisture, further decreasing water availability during the already-dry summer months. Increases in atmospheric water vapor (due to rising sea surface temperatures in the oceanic regions that are the moisture sources for Colorado precipitation) have the potential to increase the frequency and intensity of heavy precipitation events.
Map of the contiguous United States showing the projected changes in total winter precipitation by the middle of this century as described in the caption. The state of Colorado is outlined in black.
Legend values range from less than negative 10 to greater than positive 15 percent. Note: unless otherwise specified, projected values are not statistically significant.
Colorado
Projected increases in total winter precipitation are as follows: up to 5 percent along slivers of the southwestern border with New Mexico and southeastern borders with Nebraska and Oklahoma; 10 to 15 percent in the northeast, with statistically significant increases in the 10 to 15 percent range along the north-central border with Wyoming; and 5 to 10 percent across the remainder of the state.
Contiguous US
Projected increases in total winter precipitation are as follows: up to 5 percent across a narrow swath running westward from western Georgia to southern California; 5 to 10 percent in the Southeast, Mid-Atlantic, southern Midwest, portions of the Great Plains, and most of the West; and 10 to 15 percent in the majority of the Northeast and upper Midwest as well as portions of the northern Great Plains and Intermountain West, with statistically significant increases in the 10 to 15 percent range for the Northeast, the northernmost regions of the upper Midwest, and portions of the northern Great Plains.
Projected decreases are as follows: up to 5 percent for southern regions of the Southwest and northern and central Texas; 5 to 10 percent for southern New Mexico and western Texas; and 5 to 10 percent or greater for southwestern Texas.
Higher temperatures are expected to increase the rate of soil moisture loss, leading to more intense drought conditions, and with so many river basins originating in the state, any changes in precipitation patterns pose a risk to water supplies for cities and farms across the region. Increased drought intensity, along with a possible decrease in summer precipitation for some parts of the state, is projected to increase the frequency and severity of wildfires.
SOURCES
- CCC, n.d.: Learn About Colorado’s Climate. Colorado State University, Colorado Climate Center, Fort Collins, CO. https://climate.colostate.edu/co_climate.html
- Childs, S.J. and R.S. Schumacher, 2019: An updated severe hail and tornado climatology for eastern Colorado. Journal of Applied Meteorology and Climatology, 58 (10), 2273–2293. https://doi.org/10.1175/JAMC-D-19-0098.1
- Cook, E.R., U. Lall, C. Woodhouse, and D.M. Meko, 2008: North American Drought Atlas, Version 2a [Summer PDSI Reconstructions Before 1895]. National Oceanic and Atmospheric Administration, National Centers for Environmental Information, Asheville, NC, accessed June 9, 2025. https://www.ncdc.noaa.gov/paleo-search/study/6319
- HPRCC, n.d.: Climate Summaries. University of Nebraska–Lincoln, High Plains Regional Climate Center, accessed June 9, 2025. https://hprcc.unl.edu/climatesummaries.php
- Ingraham, J., 2025: Colorado's snowpack is fourth lowest in nearly 40 years, struggled to reach average. The Denver Gazette, May 1, 2025. https://web.archive.org/web/20250504004250/https://denvergazette.com/outtherecolorado/outdoors/whiteout/colorado-snowpack-update-winter-2025-april-30/article_8ea2a471-74b1-4827-89ad-9b7e8a408105.html
- Kunkel, K.E., L.E. Stevens, S.E. Stevens, L. Sun, E. Janssen, D. Wuebbles, K.T. Redmond, and J.G. Dobson, 2013: Regional Climate Trends and Scenarios for the U.S. National Climate Assessment Part 5. Climate of the Southwest U.S. NOAA Technical Report NESDIS 142-5. National Oceanic and Atmospheric Administration, National Environmental Satellite, Data, and Information Service, Washington, DC, 87 pp. https://nesdis-prod.s3.amazonaws.com/migrated/NOAA_NESDIS_Tech_Report_142-5-Climate_of_the_Southwest_U.S.pdf
- Maranghides, A., 2015: Presentation on WUI Fires—Data Collection and Case Studies (32 Slides). National Institute of Standards and Technology, Engineering Laboratory, Gaithersburg, MD. https://www.nist.gov/system/files/documents/2017/05/09/05-3_NCST-2015-WUI-Data-and-Case-Studies-Presentation.pdf
- NCDC, n.d.: Climate of Colorado. National Oceanic and Atmospheric Administration, National Climatic Data Center, Asheville, NC, 7 pp. https://www.ncei.noaa.gov/data/climate-normals-deprecated/access/clim60/states/Clim_CO_01.pdf
- NCEI, n.d.: Climate at a Glance. National Oceanic and Atmospheric Administration, National Centers for Environmental Information, accessed June 9, 2025. https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/
- NCEI, n.d.: Drought Report. National Oceanic and Atmospheric Administration, National Centers for Environmental Information, accessed June 9, 2025. https://www.ncei.noaa.gov/access/monitoring/monthly-report/drought
- NCEI, n.d.: Drought Variability [Data Access: Palmer Drought Index Studies: North American Drought Atlas (NADA) (Version 2a)]. National Oceanic and Atmospheric Administration, National Centers for Environmental Information, accessed June 9, 2025. https://www.ncei.noaa.gov/products/paleoclimatology/drought-variability
- NCEI, n.d.: National Climate Report. National Oceanic and Atmospheric Administration, National Centers for Environmental Information, accessed June 9, 2025. https://www.ncei.noaa.gov/access/monitoring/monthly-report/national
- NCEI, n.d.: State Climate Extremes Committee (SCEC) Records—Colorado. National Oceanic and Atmospheric Administration, National Centers for Environmental Information, accessed June 9, 2025. https://www.ncei.noaa.gov/access/monitoring/scec/records/co/hail
- NCEI, n.d.: U.S. Billion-Dollar Weather and Climate Disasters. National Oceanic and Atmospheric Administration, National Centers for Environmental Information, Asheville, NC, accessed June 9, 2025. https://www.ncdc.noaa.gov/billions/
- NCEI, n.d.: U.S. Climate Normals. National Oceanic and Atmospheric Administration, National Centers for Environmental Information, accessed June 9, 2025. https://www.ncei.noaa.gov/products/land-based-station/us-climate-normals
- NCEI, n.d.: Wildfires Report. National Oceanic and Atmospheric Administration, National Centers for Environmental Information, accessed June 9, 2025. https://www.ncei.noaa.gov/access/monitoring/monthly-report/fire
- NWCC, n.d.: Snowpack: Snow Water Equivalent (SWE) and Snow Depth—Colorado. U.S. Department of Agriculture, Natural Resources Conservation Service, National Water and Climate Center, accessed June 9, 2025. https://www.nrcs.usda.gov/wps/portal/wcc/home/snowClimateMonitoring/snowpack/
- Schumacher, R., 2024: A whopper of a snowstorm. Colorado Climate Blog, November 18, 2024. Colorado State University, Colorado Climate Center. https://climate.colostate.edu/blog/index.php/2024/11/18/a-whopper-of-a-snowstorm/
- USGCRP, 2017: Climate Science Special Report: Fourth National Climate Assessment, Volume I. Wuebbles, D.J., D.W. Fahey, K.A. Hibbard, D.J. Dokken, B.C. Stewart, and T.K. Maycock, Eds. U.S. Global Change Research Program, Washington, DC, USA, 470 pp. https://repository.library.noaa.gov/view/noaa/19486
- USGCRP, 2018: Impacts, Risks, and Adaptation in the United States: Fourth National Climate Assessment, Volume II. Reidmiller, D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. Maycock, and B.C. Stewart, Eds. U.S. Global Change Research Program, Washington, DC, USA, 1515 pp. https://repository.library.noaa.gov/view/noaa/19487
- USGCRP, 2023: Fifth National Climate Assessment. Crimmins, A.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, B.C. Stewart, and T.K. Maycock, Eds. U.S. Global Change Research Program, Washington, DC, USA. https://repository.library.noaa.gov/view/noaa/61592