2021 Weather In Review: Shenandoah National Park

NPS / N. Lewis

In order to better understand ecosystem health in national parks, the Mid-Atlantic Inventory and Monitoring Network measures ecosystem "vital signs" across the Mid-Atlantic region. One of those vital signs is weather and climate. Below is a summary of 2021 weather conditions at Shenandoah National Park.

This brief provides county-scale weather data averaged from all of the counties surrounding the park, including data from 1895–2021 (i.e. period of record). These counties include Albemarle, Augusta, Greene, Madison, Page, Rappahannock, Rockingham, and Warren counties, VA. Individual weather station data may vary from what is reported here. In particular, high elevations in the park may have experienced weather conditions that are different from those displayed in this brief. Data and analyses herein are courtesy of the National Oceanic and Atmospheric Administration's (NOAA) Climate at a Glance Program.

Weather vs. Climate

First of all, what is the difference between weather and climate? Weather consists of the short-term (minutes to months) changes in the atmosphere. Weather is what is happening outside at this very moment, be it rain, snow, or just a warm sunny day. Climate is what you expect to see based on long-term patterns of over 30 years or more. An easy way to remember the difference is that climate is what you might expect, like a hot summer, and weather is what you get, like a warm rainy day.

The following information includes a discussion of 2021 weather placed in the context of long-term climate (i.e. how did 2021 compare to a "normal" year?).

2021 Summary

In all, 2021 was much warmer than average and had below-normal precipitation. The year ended as the 4^th warmest and 41^st driest on record. Data indicate that over the long term, annual average temperature and annual total precipitation have both increased (+0.17 °F per decade and +0.42 inches per decade, respectively).

Temperature

In total, 2021 was the 4^th warmest year recorded in the counties surrounding the park, and all seasons were warmer than normal (Figure 1). Ten months had higher than normal temperatures with March, October, and December all being more than 4 °F above long-term averages (Table 1).

Figure 1. Seasonal and annual temperature rankings. An arrow at the top of the figure would represent the warmest year/season on record (since 1895); at the bottom, the coldest year/season on record. Data are available at https://www.ncdc.noaa.gov/cag/county/rankings.

_{Table 1. Monthly and annual average temperature and departure from long-term averages. Departures from average show how different 2021 was compared to relevant averages from 1895-2020.}

Month/Year	Average temperature (°F)	Departure from long-term average (°F)
January	34.8	+2.9
February	34.4	+0.4
March	46.5	+4.2
April	54.0	+1.9
May	61.0	-0.5
June	70.8	+1.6
July	75.2	+2.1
August	75.2	+3.7
September	67.1	+1.8
October	60.8	+6.5
November	43.2	-0.6
December	44.1	+9.5
2021	55.6	+2.8

Precipitation

The year 2021 was the 41^st driest year recorded across the park’s eight counties (Figure 2). The summer was moderately wet, though the other seasons were relatively dry. In total, 37.5 inches of precipitation fell, 3.4 inches less than the long-term average (Table 2).

Figure 2. Seasonal and annual precipitation rankings. An arrow at the top of the figure would represent the wettest year/season on record (since 1895); at the bottom, the driest year/season on record. Data are available at https://www.ncdc.noaa.gov/cag/county/rankings.

_{Table 2. Monthly and annual total precipitation and departure from long-term averages. Departures from average show how different 2021 was compared to relevant averages from 1895-2020.}

Month/Year	Total precipitation (in.)	Departure from long-term average (in.)
January	2.00	-0.85
February	3.43	+0.96
March	1.75	-1.55
April	3.42	+0.16
May	1.99	-1.98
June	4.05	-0.07
July	2.67	-1.43
August	6.59	+2.54
September	5.83	+2.23
October	4.33	+0.96
November	1.10	-1.77
December	0.33	-2.59
2021	37.50	-3.41

Temperature and Precipitation Trends
(1895-2021)

Data for counties surrounding the park indicate that annual average temperature has increased approximately +0.17 °F per decade and annual total precipitation has increased approximately +0.42 inches per decade since 1895 (Figure 3).

National Park Service scientists have forecast future changes in climate too. Models estimate that by 2100, annual average temperature at the park will increase by 3.1–8.8 °F (from a best-case to worst-case scenario, respectively). Annual total precipitation is expected to increase by 8–14% (see Gonzalez et al., 2018 for details).

Figure 3. Annual average temperature (°F) and annual total precipitation (in.) from 1895–2021 for counties surrounding the park. Dashed lines represent linear estimates of change. Data are available at https://www.ncdc.noaa.gov/cag/county/time-series.

Climate Change

Today's rapid climate change challenges national parks in ways we've never seen before. Wildlife migrations are altered, increasingly destructive storms threaten cultural resources and park facilities, habitat is disrupted—the list goes on. Learn more about climate change at Shenandoah National Park.


For more information, contact Mid-Atlantic Network Biologist, Jeb Wofford, or read more about the Mid-Atlantic Network's weather and climate monitoring program.

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