Average temperatures have increased slightly less than 1°F since the early 20th century. Under a higher emissions pathway, historically unprecedented warming is projected by the end of the 21st century, with increases in heat wave intensity and decreases in cold wave intensity.
Total precipitation amounts and the number of extreme precipitation events have been above average in the 21st century. Winter and spring precipitation amounts are projected to increase, as well as the number and intensity of extreme precipitation events, posing an increased risk of flooding.
Naturally occurring droughts are projected to be more intense in the future due to temperature-caused increases in the rate of soil moisture loss during dry spells.
The climate of West Virginia is characterized by moderately cold winters and warm and humid summers. The polar jet stream, located near or over the Northeast region during the winter, brings frequent storm systems, which cause cloudy skies, windy conditions, and precipitation. Extreme events that affect the state include floods, droughts, heat and cold waves, ice storms, remnants of hurricanes, and snowstorms, including nor’easters. Due to the state’s rugged topography, climate conditions vary considerably. West Virginia has the highest average elevation of any state east of the Mississippi River, which moderates summer temperatures. Average minimum winter temperatures range from the low 20s (°F) in the mountainous central and northeastern portions of the state to around 30°F in the far south. Average maximum summer temperatures range from around 85°F in the southwest near the Ohio River to less than 80°F in the east-central mountains. The central portion of West Virginia receives 50 or more inches of precipitation, while around 40 inches falls in the west along the Ohio River. To the west of the state’s Eastern Panhandle, a “rain shadow” exists, where average precipitation drops down to about 35 inches each year.
West Virginia has experienced a less than 1°F increase in temperature since the early 20th century. Temperatures in West Virginia increased during the early part of the 20th century and were then followed by a period of cooling. Gradual warming has occurred since the early 1980s to above long-term averages in the 21st century (Figure 1) and slightly warmer than the previous warmest periods of the 1930s and early 1950s. The number of very hot days (daytime maximum temperatures above 95°F) in West Virginia has been below average in the 21st century (Figure 2). The number of warm nights (nighttime minimum temperatures above 70°F) does not show any long-term trend but there have been above average numbers during the last five years (Figure 3). The number of very cold nights (minimum temperature below 0°F) has been below average since the 1990s (Figure 4).
There is no overall trend in average precipitation in West Virginia for the 118-year period of record. Precipitation has generally been near to above average since the early 1990s. The driest multi-year periods were the early 1930s and the late-1960s, with the driest 5-year period being 1962-1966, averaging 40 inches per year, while the wettest multi-year period were the early 1900s and the 2000s, with the wettest 5-year period being 2002-2006 (averaging 48.5 inches) (Figure 5). The number of extreme precipitation events (precipitation totals greater than 2 inches) has been above average since the late 1990s, including the highest 5-year average number during 2000–2004 (Figure 6). The mountains of West Virginia are characterized by some of the highest snowfall totals east of the Mississippi River with an annual average of 100 inches of snowfall. During the winter of 2009–2010, record amounts of snowfall (more than 200 inches) occurred, with over 100 inches falling in the month of February.
West Virginia is subject to a wide array of extreme weather including tornadoes, thunderstorms, snowstorms, hurricane remnants, and flooding. Tornadoes occasionally occur (an average of two-to-five per year) and are usually weak. Flood-producing extreme precipitation over the rugged topography is the costliest and most severe natural hazard for the state. From 2005 to 2014 the state received 16 FEMA disaster declarations, 12 of which were related to severe storms and flooding events. The two most significant historical flooding events occurred in 1937 and 1985. The Great Ohio River Flood of 1937 affected numerous states, but the southwestern part of West Virginia near Huntington was the hardest hit. Heavy downpours occurred over a two-week period with rainfall averaging 6 to 12 inches throughout the region. The river level at Huntington crested at 69 feet, 19 feet above flood stage, a record that still stands today. An estimated $18 million (in 1937 dollars) in damages to homes and buildings occurred. In early November 1985, an extratropical storm, also influenced by the remnants of Hurricane Juan, generated up to 10 inches of rainfall across West Virginia. Extensive river flooding occurred mostly in the eastern portion of the state, resulting in an estimated $570 million in damages (in 1985 dollars) to 3,500 homes and 180 local businesses.
Under a higher emissions pathway, historically unprecedented warming is projected by the end of the 21st century (Figure 1). Even under a lower pathway of greenhouse gas concentrations, temperatures are projected to most likely exceed historical record levels by the middle of the 21st century. However, there is a large range of temperature increases under both pathways, and under the lower pathway, a few projections are only slightly warmer than historical records (Figure 1). Increased heat wave intensity and decreased cold wave intensity are projected.
Annual precipitation is projected to increase for West Virginia over this century (Figure 7) with those increases mostly in the winter and spring. The number and intensity of extreme precipitation events are also projected to increase. These events will likely lead to greater flood risk. Drought is a periodically-occurring natural phenomenon within the state. Higher temperatures are projected to increase the rate of loss of soil moisture during dry spells, resulting in more intense naturally-occurring droughts in the future.
Much of the state’s land cover is forested. These forests provide unique habitats for an abundance of plants and animals, some of which are endangered. For example, the state’s Red Spruce habitat occupies the largest high elevation area in the northeastern United States. Upland Red Spruce communities are highly vulnerable to climate change due to their topographic location on the highest mountaintops, low elevation barriers to dispersal, and fairly narrow temperature and precipitation tolerances. In the future, climate change may significantly alter Red Spruce forests.