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Loudoun County Climate

Loudoun County, Virginia

NOAA NCEI 1991-2020 Climate Normals
JanFebMarAprMayJunJulAugSepOctNovDec54.8°AVG °F

Avg Annual Temp

54.8°F

Annual Precip

44.4"

Annual Snowfall

Extreme Heat Days

31

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet
3.1"
2.6"
3.7"
3.5"
4.6"
4.4"
4.1"
3.6"
4.4"
3.8"
3.2"
3.4"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Growing Season & Gardening

USDA Hardiness Zone

7a

Minimum winter temperature range for plant survival

Growing Degree Days

3,711

Supports most vegetables & fruits

Last spring frost (32°F): 04/16
First fall frost (32°F): 10/26

Seasonal Overview

Comfort ZoneSpring43°63°11.8"Summer72°77°12.1"Fall45°68°11.4"Winter33°37°9.1"20°40°60°80°100°

National Comparison

Warmer than 50% of US counties
Wetter than 57% of US counties
More seasonal variation than 52% of US counties

7-Day Outlook

Forecast

Current Conditions

Air Quality

Safety

Weather Alerts

Climate Advisory: Loudoun County

Climate Verdict

Loudoun County has a mild, with an average annual temperature of 54.8°F, moderately wet with 44.4 inches of annual precipitation, occasional hot days — 30.9 per year above 90°F. This climate profile shapes everything from energy costs to outdoor recreation opportunities.

Seasonal Breakdown

Winters are cold, with January averaging 33.1°F. summers are warm — July averages 76.6°F. The 44°F seasonal variation provides noticeable but manageable change.

Outdoor & Gardening Guidance

Growing season and gardening data is currently limited for Loudoun County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.

Regional Context

Loudoun County closely matches the Virginia statewide average temperature of 56.2°F.

Climate Profile

About Loudoun County Weather

Subtropical Shifts in Northern Virginia

Loudoun County averages 54.8°F annually, aligning closely with the national median for temperate climates. The region experiences a humid subtropical environment characterized by distinct seasonal transitions.

Trailing the Commonwealth Average Temperature

At 54.8°F, Loudoun County remains slightly cooler than the Virginia state average of 55.9°F. Its location in the northern part of the state accounts for this lower temperature ranking compared to southern coastal counties.

Cooler Than Neighboring Manassas City

Loudoun's 54.8°F average is nearly a full degree cooler than Manassas city's 55.5°F. Both areas face similar precipitation patterns, with Loudoun receiving 44.4 inches of rainfall annually.

Intense Summers and Chilly January Nights

The county faces 31 extreme heat days annually when temperatures top 90°F, concentrated during the 76.6°F July peak. While snowfall data is limited for this specific station, winter averages drop to a cold 35.1°F.

Summer Heat Readiness is Critical

With a full month of 90-degree days, robust air conditioning is a necessity for Loudoun residents. The 44.4 inches of annual rain also requires well-maintained drainage systems to handle heavy Mid-Atlantic storm cycles.

Frequently Asked Questions

What is the average temperature in Loudoun County?
The average annual temperature in Loudoun County, VA is 54.8°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Loudoun County get?
Loudoun County receives an average of 44.4 inches of precipitation per year, including both rain and meltwater from snow. This is based on NOAA 30-year climate normals.
How hot does Loudoun County get in summer?
The average summer temperature (June-August) in Loudoun County is 74.5°F. The county experiences an average of 31 days per year above 90°F.
How cold are winters in Loudoun County?
The average winter temperature (December-February) in Loudoun County is 35.1°F. January, typically the coldest month, averages 33.1°F.

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Data sources: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020. Forecast and alert data from National Weather Service API. Air quality data from Open-Meteo.

Climate normals are 30-year averages of weather variables. Station data is aggregated to county level. Forecasts and alerts are fetched live and may change frequently. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.

By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor
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