Frost Dates for Hartford, Connecticut, United States of America

Coordinates: 41.764, -72.686

Growing Season

The last spring air frost in Hartford, Connecticut, United States of America typically occurs around May 9, and the first autumn air frost around Sep 20. This gives a frost-free growing season of approximately 134 days.

USDA Hardiness Zone

This location falls in USDA Hardiness Zone 5b, where the average annual extreme minimum temperature is -26.1 to -23.3°C (-15 to -10°F). This zone rating helps gardeners determine which perennial plants are likely to survive winter.

Temperature Overview

The coldest month is January, with an average low of -6°C (21°F). The warmest month is July, with an average high of 29°C (84°F).

Frost Risk Breakdown

Frost dates at three temperature thresholds: Air frost (0°C / 32°F): May 9 (last spring) to Sep 20 (first autumn). Light ground frost (-1°C / 30°F): Apr 28 (last spring) to Sep 30 (first autumn). Hard ground frost (-2°C / 28°F): Apr 12 (last spring) to Oct 14 (first autumn).

We predict your growing zone to be approximately ...

USDA Growing Zone
USDA Growing Zone - 5b

... and the frost data for your area is ...

Current Risk Level: Light Ground Frost possible

for today based on past data only.

We predict a frost free growing season at your location from May 9 to Sep 20, which provides approximately 133 frost free days.

For the less tender plants, or if you are planning to protect your plants with fleece etc, your growing season could stretch from Apr 28 to Sep 30, which provides a total of 155 days for growing.

Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
  • Hard Ground Frost possible
  • Light Ground Frost possible
  • Air Frost possible
  • Safest (unlikely)
First and last frost dates by frost type
FirstLast
Air FrostSep 20May 9
Light Ground FrostSep 30Apr 28
Hard Ground FrostOct 14Apr 12

Frost Dates for Hartford, Connecticut, United States of America | FrostDates.com