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Sullivan County Climate

Sullivan County, Tennessee

NOAA NCEI 1991-2020 Climate Normals
JanFebMarAprMayJunJulAugSepOctNovDec57.0°AVG °F

Avg Annual Temp

57.0°F

Annual Precip

44.5"

Annual Snowfall

7.1"

Extreme Heat Days

26

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
3.8"
3.9"
4.0"
3.9"
3.8"
3.8"
5.0"
3.8"
2.9"
2.5"
3.2"
3.9"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Growing Season & Gardening

USDA Hardiness Zone

7b

Minimum winter temperature range for plant survival

Growing Degree Days

4,027

Excellent for heat-loving crops

Last spring frost (32°F): 04/16
First fall frost (32°F): 10/29

Seasonal Overview

Comfort ZoneSpring48°65°11.8"Summer73°76°12.6"Fall47°69°8.5"Winter37°40°11.6"20°40°60°80°100°

National Comparison

Warmer than 60% of US counties
Wetter than 57% of US counties
More seasonal variation than 32% of US counties

7-Day Outlook

Forecast

Current Conditions

Air Quality

Safety

Weather Alerts

Climate Advisory: Sullivan County

Climate Verdict

Sullivan County has a mild, with an average annual temperature of 57.0°F, moderately wet with 44.5 inches of annual precipitation, occasional hot days — 25.65 per year above 90°F, light snow averaging 7.1 inches per year. This climate profile shapes everything from energy costs to outdoor recreation opportunities.

Seasonal Breakdown

Winters are cold, with January averaging 36.6°F. summers are warm — July averages 76.0°F. The 39°F seasonal variation provides noticeable but manageable change.

Outdoor & Gardening Guidance

The moderate temperatures support hiking, cycling, and camping comfortably in spring, summer, and fall.

Regional Context

Sullivan County closely matches the Tennessee statewide average temperature of 58.0°F, it is also noticeably drier, receiving 11.1 inches less precipitation than the state average.

Climate Profile

About Sullivan County Weather

Moderate Temperatures and Manageable Rain

Sullivan County's 57.0°F average annual temperature is slightly higher than the national median. It is drier than many of its peers, with 44.5 inches of annual precipitation.

Cooler and Drier Than Average

At 57.0°F, Sullivan is cooler than the 58.1°F Tennessee state average. It is significantly drier than the state norm, receiving over 11 inches less rain than the state average of 55.9 inches.

The Drier Side of Appalachia

Sullivan County is notably drier than its mountain neighbors to the south. Its 44.5 inches of rain is low for East Tennessee, though it shares the region's characteristic cool winter breezes.

Mild Summers and Crispy Winters

Summers are pleasant with only 26 days of extreme heat and a 74.6°F average. Winters bring a January average of 36.6°F and 7.1 inches of annual snowfall.

Enjoy More Outdoor Days

With only 26 extreme heat days, Sullivan offers more comfortable outdoor time than much of Tennessee. Residents should keep a shovel ready for the 7.1 inches of snow that typically falls each winter.

Frequently Asked Questions

What is the average temperature in Sullivan County?
The average annual temperature in Sullivan County, TN is 57.0°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Sullivan County get?
Sullivan County receives an average of 44.5 inches of precipitation per year, including both rain and meltwater from snow. This is based on NOAA 30-year climate normals.
Does it snow in Sullivan County?
Yes, Sullivan County receives an average of 7.1 inches of snowfall per year according to NOAA climate normals.
How hot does Sullivan County get in summer?
The average summer temperature (June-August) in Sullivan County is 74.6°F. The county experiences an average of 26 days per year above 90°F.
How cold are winters in Sullivan County?
The average winter temperature (December-February) in Sullivan County is 38.8°F. January, typically the coldest month, averages 36.6°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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