Frost Dates for Union Square, MA

Based on data from Boston Logan Intl AP weather station, 5 miles away

Elevation: 43 ft

Frost Dates

Last Spring Frost (50%) A 50% chance that the last spring frost has already passed by this date. Most gardeners use this as their primary planting guide. April 4
First Fall Frost (50%) A 50% chance that the first fall frost has occurred by this date. Plan to harvest or protect tender plants before this date. November 9

30% Probability

Only a 30% chance of frost remaining by this date. Use these dates for a safer planting window, especially for tender plants sensitive to cold.
Last Spring Frost April 8
First Fall Frost November 3

Hard Freeze (28°F)

Last Spring Hard Freeze March 28
First Fall Hard Freeze November 21
42.38°N, 71.10°W © OpenStreetMap

Growing Season

219 Days April 4 to November 9

USDA Hardiness Zone

Hardiness zones indicate which perennial plants can survive winter in your area. For annual vegetables, frost dates and growing season length matter more than hardiness zone.
Zone 7a

Avg. annual minimum: 0 to 5°F

Learn more

Köppen Climate

The Köppen climate classification system categorizes climates based on temperature and precipitation patterns.
Dfa Hot-Summer Continental

Hot summers and cold winters with year-round precipitation. Moderate growing season supports warm-season crops like tomatoes, peppers, and corn. Winter protection extends the harvest.

Köppen climate map

Temperature

Avg High Avg Temp Avg Low Light Frost (32°F) Hard Frost (28°F)
Temperature table
Average monthly temperatures (°F)
Month Avg High Avg Temp Avg Low
January37°30°23°
February39°32°25°
March46°38°31°
April56°49°41°
May67°58°50°
June76°68°60°
July82°74°66°
August80°73°65°
September73°66°58°
October62°55°48°
November52°45°38°
December42°36°29°

Precipitation

Precipitation table
Average monthly precipitation (inches)
MonthPrecipitation
January4.2
February4.2
March5.1
April4.3
May4.4
June4.2
July4.5
August5.2
September5.4
October4.6
November5.0
December5.2

Sunrise / Sunset

Daylight Eastern Time (ET) Longest: 15h 06m · Shortest: 8h 54m
Sunrise and sunset table
Sunrise, sunset, and daylight on the 15th of each month (Eastern Time (ET))
Month Sunrise Sunset Daylight
January7:17 AM4:30 PM9h 14m
February6:48 AM5:09 PM10h 21m
March7:04 AM6:43 PM11h 39m
April6:09 AM7:19 PM13h 10m
May5:28 AM7:53 PM14h 25m
June5:12 AM8:17 PM15h 05m
July5:25 AM8:14 PM14h 49m
August5:57 AM7:40 PM13h 43m
September6:30 AM6:47 PM12h 16m
October7:05 AM5:54 PM10h 49m
November6:43 AM4:15 PM9h 32m
December7:13 AM4:07 PM8h 55m

Nearby Stations

Jamaica Plain, MA April 19 - October 23 Hingham, MAApril 25 - October 22 Blue Hill, MA April 19 - October 24 Blue Hill Coop, MA April 18 - October 26 Marblehead, MA April 25 - October 20 Reading, MAApril 25 - October 17

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