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Suffolk County Climate

Suffolk County, Massachusetts

NOAA NCEI 1991-2020 Climate Normals
JanFebMarAprMayJunJulAugSepOctNovDec51.5°AVG °F

Avg Annual Temp

51.5°F

Annual Precip

46.5"

Annual Snowfall

49.2"

Extreme Heat Days

17

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
3.6"
3.4"
4.3"
4.0"
3.4"
4.0"
3.4"
3.5"
3.8"
4.5"
3.8"
4.7"
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

3,048

Supports most vegetables & fruits

Last spring frost (32°F): 04/19
First fall frost (32°F): 11/09

Seasonal Overview

Comfort ZoneSpring38°59°11.8"Summer68°74°10.9"Fall44°65°12.1"Winter29°35°11.7"20°40°60°80°100°

National Comparison

Warmer than 37% of US counties
Wetter than 63% of US counties
More seasonal variation than 62% of US counties

7-Day Outlook

Forecast

Current Conditions

Air Quality

Safety

Weather Alerts

Climate Advisory: Suffolk County

Climate Verdict

Suffolk County has a mild, with an average annual temperature of 51.5°F, moderately wet with 46.5 inches of annual precipitation, rare extreme heat with only 17.15 days above 90°F annually, moderate snowfall of 49.2 inches annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.

Seasonal Breakdown

Winters are cold, with January averaging 29.0°F. summers are warm — July averages 74.3°F. The 45°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

Suffolk County closely matches the Massachusetts statewide average temperature of 49.5°F.

Climate Profile

About Suffolk County Weather

Massachusetts' Urban Heat Hub

Suffolk County is the warmest in this group, with an average annual temperature of 51.5°F. This exceeds the national median, largely due to the urban heat island effect centered in Boston.

The State's Temperature Leader

Suffolk ranks well above the 49.5°F state average, making it the warmest county in Massachusetts. Its precipitation levels are slightly below the state average, totaling 46.5 inches annually.

Warmer Than Surrounding Suburbs

Suffolk is nearly two degrees warmer on average than neighboring Middlesex County. It also experiences more extreme heat days (17) than Norfolk (14) or Middlesex (15) due to its dense urban footprint.

Sizzling Julys and Brisk Winters

Summer peaks in July with a 74.3°F average, the highest in the region, including 17 days over 90°F. Despite the heat, the county still sees 49.2 inches of snow during the 31.6°F winter season.

Cooling is the Priority

Robust air conditioning is vital here to combat the 17 days of extreme heat and high urban temperatures. Residents should also keep snow shovels ready for the nearly 50 inches of annual snowfall.

Frequently Asked Questions

What is the average temperature in Suffolk County?
The average annual temperature in Suffolk County, MA is 51.5°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Suffolk County get?
Suffolk County receives an average of 46.5 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 Suffolk County?
Yes, Suffolk County receives an average of 49.2 inches of snowfall per year according to NOAA climate normals.
How hot does Suffolk County get in summer?
The average summer temperature (June-August) in Suffolk County is 71.7°F. The county experiences an average of 17 days per year above 90°F.
How cold are winters in Suffolk County?
The average winter temperature (December-February) in Suffolk County is 31.6°F. January, typically the coldest month, averages 29.0°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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