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Washtenaw County Climate

Washtenaw County, Michigan

NOAA NCEI 1991-2020 Climate Normals
JanFebMarAprMayJunJulAugSepOctNovDec48.3°AVG °F

Avg Annual Temp

48.3°F

Annual Precip

34.8"

Annual Snowfall

51.2"

Extreme Heat Days

13

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
2.4"
2.0"
2.4"
3.2"
3.8"
3.6"
3.5"
3.3"
2.9"
2.8"
2.6"
2.2"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Growing Season & Gardening

USDA Hardiness Zone

6a

Minimum winter temperature range for plant survival

Growing Degree Days

2,686

Supports most vegetables & fruits

Last spring frost (32°F): 05/02
First fall frost (32°F): 10/11

Seasonal Overview

Comfort ZoneSpring35°58°9.4"Summer68°71°10.4"Fall39°62°8.3"Winter24°29°6.7"20°40°60°80°100°

National Comparison

Warmer than 24% of US counties
Wetter than 34% of US counties
More seasonal variation than 73% of US counties

7-Day Outlook

Forecast

Current Conditions

Air Quality

Safety

Weather Alerts

Climate Advisory: Washtenaw County

Climate Verdict

Washtenaw County has a cool, averaging 48.3°F annually, moderate rainfall of 34.8 inches per year, rare extreme heat with only 13.271428571428572 days above 90°F annually, moderate snowfall of 51.2 inches annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.

Seasonal Breakdown

Winters are very cold — January averages 23.6°F. summers are warm — July averages 71.5°F. The 48°F seasonal variation provides noticeable but manageable change.

Outdoor & Gardening Guidance

Winter sports enthusiasts benefit from reliable snow cover for 3-4 months annually.

Regional Context

Washtenaw County closely matches the Michigan statewide average temperature of 45.7°F.

Climate Profile

About Washtenaw County Weather

Balanced Seasonal Temps Below Median

Washtenaw County averages 48.3°F annually, placing it below the national median temperature. It receives 34.8 inches of precipitation, which is consistent with the standard for the Great Lakes region.

Above the State Average Temperature

The county's 48.3°F annual average is nearly three degrees warmer than the Michigan state average of 45.7°F. This reflects its southern location and slightly milder seasonal transitions.

Cooler Than Neighboring Wayne County

Washtenaw is slightly cooler than Wayne County to the east, which averages 50.1°F. However, it is warmer than northern neighbors like Tuscola, which averages only 46.3°F.

Hot Summers and Significant Snow

July peaks at an average of 71.5°F with 13 days reaching above 90°F. Winter brings a notable 51.2 inches of snow and a January average of 23.6°F.

Plan for Diverse Weather Extremes

Residents should prepare for 51 inches of snow, which is higher than many surrounding counties. Efficient air conditioning is also useful for the 13 annual days of extreme heat.

Frequently Asked Questions

What is the average temperature in Washtenaw County?
The average annual temperature in Washtenaw County, MI is 48.3°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Washtenaw County get?
Washtenaw County receives an average of 34.8 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 Washtenaw County?
Yes, Washtenaw County receives an average of 51.2 inches of snowfall per year according to NOAA climate normals.
How hot does Washtenaw County get in summer?
The average summer temperature (June-August) in Washtenaw County is 69.6°F. The county experiences an average of 13 days per year above 90°F.
How cold are winters in Washtenaw County?
The average winter temperature (December-February) in Washtenaw County is 26.1°F. January, typically the coldest month, averages 23.6°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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