Nevada has a highly diverse climate due its large elevation range, from less than 500 feet at the southernmost tip to more than 13,000 feet at the peaks of the White Mountains and the Snake Range. Much of the state lies within the Great Basin, a region between the Rockies and the Sierra Nevada that encompasses numerous small mountain ranges and high-elevation desert valleys. Due to the climate and rugged mountainous terrain, much of the land is sparsely populated. The majority of residents live in two concentrated urban areas, the Las Vegas and Reno–Sparks metro areas, which are supported by water from, respectively, the Colorado River via Lake Mead and the Truckee River, which originates in Lake Tahoe. Las Vegas is one of the hottest cities in the United States, with summer high temperatures averaging almost 102°F and regularly exceeding 110°F. Typical summer high temperatures across the rest of the state range from less than 75°F at high elevations to more than 100°F in the southern deserts (1991–2020 averages). Average winter low temperatures range from less than 20°F in the northeastern corner of the state to around 45°F in the far south. Nevada is the Nation’s driest state due to its location on the eastern side of the Sierra Nevada, which blocks much of the Pacific Ocean’s moisture from reaching the state. Regionally, annual average precipitation varies from around 4 inches in some southern low-elevation locations to more than 50 inches on high mountain peaks of the Sierra Nevada. Statewide annual average (1895–2024) precipitation is only 10.2 inches.
Time series of observed and projected temperature change (in degrees Fahrenheit) for Nevada from 1900 to 2100 as described in the caption.
Y-axis values range from negative 4 to positive 18 degrees. Observed annual temperatures from 1900 to 2024 show variability and range from negative 2.0 to positive 3.8 degrees. By the end of the century, projected increases in temperature range from 1.8 to 7.6 degrees under the lower emissions pathway, from 4.3 to 10.7 degrees under the intermediate pathway, and from 8.4 to 17.3 degrees under the higher pathway.
Annual average temperatures in Nevada have increased about 2.5°F since the beginning of the 20th century (Figure 1), and 2015–2024 was the warmest decade on record. The numbers of very hot days and warm nights have increased greatly since the early 1980s and late 1970s, respectively, with the highest 5-year averages for both recorded for the 2020–2024 period (Figures 2a and 2b). The state is one of the most urbanized in the Nation, with about 94% of the population living in areas defined as urban. Heat absorbed and emitted by buildings and pavement, as well as other aspects of urban environments, makes cities even warmer than the surrounding countryside, a phenomenon known as the urban heat island effect. Local warming trends are exacerbated by the urban heat island effect, especially in Las Vegas, which has experienced explosive growth and is particularly vulnerable to extreme heat. Las Vegas set a record-high temperature of 120°F on July 7, 2024.
Two sets of paired graphs of the observed annual number of (a) very hot days and (b) warm nights for Nevada (top) from 1950 to 2024 and for the contiguous United States (bottom) from 1900 to 2024 as described in the caption.
Annual and 5-year values show variability in all graphs.
Panel A: Very Hot Days
Nevada
Y-axis values range from 10 to 60 days. Annual values range from 13.6 to 53.8 days. Five-year values are all below the long-term average of 31.3 days between 1950 and 1999 but are all above average since 2000. The 1980 to 1984 period has the lowest 5-year value at 23.6 days, and the 2020 to 2024 period has the highest at 46.1 days.
Contiguous US
Y-axis values range from 4 to 40 days. Annual values range from 7.0 to 36.6 days. Five-year values are below 16 days between 1900 and 1909, all near or above 16 days between 1910 and 1959, and all near or below 16 days since 1960 except for the 1980 to 1984, 2010 to 2014, and 2020 to 2024 periods, which are slightly above 16 days. The 1990 to 1994 period has the lowest 5-year value at 12.5 days, and the 1930 to 1934 and 1935 to 1939 periods have the highest at 27.1 and 24.9 days, respectively.
Panel B: Warm Nights
Nevada
Y-axis values range from 2 to 16 nights. Annual values range from 3.3 to 14.3 nights. Five-year values are all below the long-term average of 6.6 nights between 1950 and 1999 but are all above average since 2000. The 1975 to 1979 period has the lowest 5-year value at 4.6 nights, and the 2020 to 2024 period has the highest at 11.2 nights.
Contiguous US
Y-axis values range from 4 to 28 nights. Annual values range from 7.5 to 26.2 nights. Five-year values are mostly near or below 16 nights between 1900 and 1994. Exceptions include the 1930 to 1934 and 1935 to 1939 periods with more than 18 nights. An upward trend is evident since the 1970 to 1974 period, which has the lowest 5-year value at 12.1 nights. All 5-year values since 1995 are above 18 nights. The 2010 to 2014 period has the highest 5-year value at 20.4 nights.
Statewide total annual precipitation has ranged from a low of 5.9 inches in 2020 to a high of 17.8 inches in 1983 (Figure 3). Since the relatively wet conditions of the late 1990s, total annual precipitation has generally been below average, but there is no overall trend across the 130-year period of record (1895–2024). Seasonal precipitation patterns vary across the state, with most locations receiving the majority of their precipitation during the winter months. However, southern areas, including Las Vegas, can experience intense summer rainfall from the North American Monsoon, which frequently leads to disruptive flooding in the Las Vegas Valley. Flooding can also occur outside of the monsoon season. In January 1997, heavy rainfall on top of above-average snowpack led to rapid snowmelt, causing multiple levee failures and extensive flooding along the Truckee River. The flooding caused extensive damage and two fatalities in the Reno area. Flooding occurred again in the region in December 2005, damaging around 900 businesses in the industrial town of Sparks.
Graph of the observed total annual precipitation for Nevada from 1895 to 2024 as described in the caption.
Y-axis values range from 4 to 20 inches. Annual values show year-to-year variability and range from 5.9 to 17.8 inches. Five-year values also show variability, showing no clear trend, and are mostly near or below the long-term average of 10.2 inches across the entire period. Exceptions include the 1905 to 1909, 1980 to 1984, and 1995 to 1999 periods, which have the highest 5-year values at 12.2, 13.5, and 12.1 inches, respectively. The 1925 to 1929 period has the lowest 5-year value at 8.8 inches.
Drought is a common occurrence in this arid state, which has a long historical record of extended dry periods (Figure 4). Parts of Nevada suffered from droughts throughout most of the 20th century and into this century. The 21st-century droughts have been among the most severe on record, broken by shorter wet periods than earlier droughts. Exceptional drought conditions (as defined by the US Drought Monitor) occurred in Nevada from 2013–2016 and again from 2020–2022. The drought of the 2020s was one of the warmest droughts in the modern historical record (1895–2024), and the high temperatures worsened drought conditions by increasing evapotranspiration from plants and soils and evaporation from reservoirs. The region’s persistent drought affects not only people but also ecosystems—leading, for example, to massive die-offs of pinyon pines, which in turn can cause massive outbreaks of bark beetles that then attack other tree species. Drought can also exacerbate wildfire risk, which is a concern for the state. Following the national drought of 2012, western wildfires burned an estimated 9 million acres across eight states, including Nevada, causing more than $1 billion in damages. In 2021, wildfires burned more than 120,000 acres in the state, with lightning-sparked blazes responsible for most of the destruction.
Line graph of the Nevada 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 6.4. Annual values for most years fall between negative 3 and positive 2, but values reaching negative 4 or positive 3 are common. The 20-year running average also shows variability, with values ranging from negative 1.9 to positive 1.1. Since the beginning of the modern era (red line), the running average is generally high in the positive range until the late 1910s, then fluctuates above and below 0 until the 1990s. Since then, the running average shows a downward trend, reaching a low of negative 1.3 in 2014.
Drought and record-low runoff in the Colorado River Basin have placed serious strain on Lake Mead, the largest man-made reservoir in the United States and a key source of water for southern Nevada as well as Arizona, southern California, and northern Mexico. According to the US Bureau of Reclamation (USBR) the period from 2000 through 2022 saw the basin’s lowest 23-year inflow in the historical record and one of the lowest in the past 1,200 years. Since reaching high levels in the late 1990s, Lake Mead reservoir levels have been falling, reaching a historic low in 2022 (Figure 5). In August 2021, a federal water shortage was declared by the USBR, resulting in reduced water allocations for Arizona, Nevada, and Mexico. Due to aggressive conservation policies, metropolitan areas have been able to manage the reductions in water supplies, but water supplies have been strained in agricultural areas that rely on surface water.
Time series of annual average water levels for Lake Mead at Hoover Dam from 1950 to 2024 as described in the caption.
Y-axis values range from 1,050 to 1,230 feet in elevation. Annual values (blue line) show year-to-year variability and range from a high of 1,215 feet in 1983 to a low of 1,050 feet in 2022. Annual values are mostly between 1,110 and 1,190 feet from the beginning of the period through the early 1970s and mostly between 1,170 and 1,210 feet from the late 1970s through the early 2000s. A steep downward trend is evident since the late 1990s. In 2021, lake elevations crossed the threshold for reduced water allocations (red dashed line at 1,075 feet) and have remained below that threshold ever since; however, a 16-foot rise in elevation to 1,067 feet is shown between 2022 and 2024.
Snowpack is a key source of water for Lake Tahoe, with snowmelt contributing to refilling of the lake every spring. Lake levels then slowly decrease throughout the year. Warm and/or dry years lead to low snowpack (Figure 6) and associated decreases in water levels in the lake, which can affect water supplies for agriculture and communities in downstream areas, including Reno and Sparks. Since 1900, Lake Tahoe water levels have fallen below the natural rim several times (Figure 7).
Time series of the annual variations in the April 1 snow water equivalent at Mount Rose, Nevada, from 1910 to 2024 as described in the caption.
Y-axis values range from 0 to 90 inches. Annual values show year-to-year variability and range from 9.0 inches in 1926 to 81.8 inches in 2017. Annual values are mostly between 15 and 50 inches across the entire period. The highest values at more than 70 inches occurred in 1969, 2017, and 2023, and the lowest values at less than 15 inches occurred in 1926, 1931, 1934, 1992, and 2015.
Time series of annual maximum and minimum water levels at Lake Tahoe from 1900 to 2024 as described in the caption.
Y-axis values range from 6,220 to 6,232 feet. Annual values show wide year-to-year variability, with maximum and minimum values following a somewhat parallel pattern. Maximum values range from 6,222 feet in 1992 to 6,231 feet in 1907, and minimum values range from 6,220 feet in 1992 to 6,228 feet in 1916. From 1900 to the mid-1910s, maximum values are mostly between 6,228 and 6,230 feet and minimum values between 6,226 and 6,227 feet. Between the late 1910s and mid-1930s, there is a gradual decline, with maximum values dropping from more than 6,229 feet to less than 6,224 feet and minimum values from 6,228 feet to less than 6,222 feet. In the late 1930s, there is a sharp increase in both values. Between the mid-1930s and early 1980s, maximum values are mostly between 6,226 and 6,229 feet and minimum values between 6,224 and 6,227 feet. There is a sharp decline in both values in the late 1980s, with maximum values mostly between 6,222 and 6,223 feet and minimum values between 6,220 and 6,223. In the mid-1990s, there is a sharp rise in both values. Since then, maximum values are mostly between 6,225 and 6,229 feet and minimum values between 6,223 and 6,227 feet.
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. Extreme high temperatures are projected to increase substantially, with potentially large impacts in the very hot southern deserts, particularly the Las Vegas metro area, where 70% of the state’s population resides. Extreme heat, combined with the urban heat island effect, can result in poor air quality and an increased risk of chronic respiratory conditions and heat stress.
Rising temperatures in Nevada are expected to raise the snow line (the average lowest elevation at which snow falls) and increase the likelihood that precipitation falls as rain rather than 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 spring temperatures are also expected to result in earlier melting of the snowpack, further decreasing water availability during the already-dry summer months.
Under the intermediate emissions pathway, projections indicate increases in total annual precipitation by midcentury across most of Nevada, with decreases projected for the southern tip of the state; however, the projected changes are not statistically significant (Figure 8). There is similar uncertainty in projections for seasonal precipitation, although models generally indicate statewide increases in winter precipitation and both increases and decreases in spring, summer, and fall.
Map of the contiguous United States showing the projected changes in total annual precipitation by the middle of this century as described in the caption. The state of Nevada 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.
Nevada
Nearly all of Nevada is projected to see increases in total annual precipitation of up to 10 percent, while the southern tip of the state is projected to see decreases of up to 5 percent.
Contiguous US
Projected increases in total annual precipitation are as follows: up to 5 percent for most of the Southeast, as well as the central Midwest, central Great Plains, central West, and Northwest; and 5 to 10 percent for all of the Northeast, as well as portions of the Mid-Atlantic, Southeast, northern Midwest, northern Great Plains, and Pacific Northwest, with statistically significant increases in the 5 to 10 percent range for the Northeast, northeastern Midwest, and portions of the northern Great Plains and Pacific Northwest.
Projected decreases of up to 5 percent are expected across most of Texas, New Mexico, and Arizona, as well as southern California.
Higher temperatures are projected to decrease the amount of water in the mountain snowpack and increase the demand for water. Rising temperatures are also expected to increase evaporation rates, reducing streamflow and soil moisture. Thus, the intensity of future droughts is expected to increase, as is the risk of wildfires in Nevada and surrounding states. Increases in population and potentially decreased water flow from the Colorado River may lead to future water security issues across the state.
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