Frost dates / Connecticut / West Haven

Frost dates in West Haven, CT

The station on this page is NEW HAVEN TWEED AP, CT US (USW00014758), 4.2 miles from the city point. Population in the Census 2024 estimate is 55,379.

Zone 7aUSDA average annual extreme minimum 0°F to 5°F, from ZIP 06516 (0.1 miles from the city point used on this page).

Median last 32°F is April 17. Median first 32°F is October 27. The 50% growing-season length is 193 days. The green band runs from the median last frost to the median first frost. Thin ticks mark the 10%, 50%, and 90% dates.

Outside the median season Growing seasonTicks: 10%, 50%, and 90%

Last 32°F in spring

NCEI’s probability is the chance the last spring minimum of 32°F or lower occurs on or after the date.

Probability	Date	How to read it
90%	April 2	Earlier date. A last 32°F on or after this day is common.
50%	April 17	Median.
10%	May 1	Later date. A last 32°F on or after this day is uncommon.

First 32°F in fall

NCEI’s probability is the chance the first autumn minimum of 32°F or lower occurs on or before the date.

Probability	Date	How to read it
10%	October 11	Earlier date. A first 32°F on or before this day is uncommon.
50%	October 27	Median.
90%	November 8	Later date. A first 32°F on or before this day is common.

32°F growing-season length

Days between the last spring 32°F and the first autumn 32°F. The figure is a length the season meets or exceeds at that probability, from NCEI, not a subtraction done on this site.

Probability the season is at least this long	Days
10%	211
50%	193
90%	174

28°F threshold

	10%	50%	90%
Last, on or after	April 18	April 4	March 22
First, on or before	October 22	November 6	November 21
Season at least	236 days	215 days	195 days

36°F threshold

	10%	50%	90%
Last, on or after	May 12	April 30	April 17
First, on or before	October 4	October 15	November 1
Season at least	189 days	170 days	152 days

Station NEW HAVEN TWEED AP, CT US (USW00014758). Completeness flag R, 19 years used for the 32°F dates. NCEI’s annual probability of at least one day at or below 32°F is 100%. Freeze dates are conditional on that threshold occurring. Elevation 0.9 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.

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West Haven, CT

Zone 7aAverage annual extreme minimum 0°F to 5°F

Outside the median season Growing seasonTicks: 10%, 50%, and 90%

Connecticut. Nearest qualified station: NEW HAVEN TWEED AP, CT US (USW00014758), 4.2 miles. Median last 32°F April 17. Median first 32°F October 27. The 50% growing-season length is 193 days.

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32°F probabilities at this station

	10%	50%	90%
Last 32°F on or after	May 1	April 17	April 2
First 32°F on or before	October 11	October 27	November 8

Column order matches the NCEI file: for the last freeze, 10% is the later date and 90% is the earlier date. How to read the probabilities.

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Planting calendar

Frost dates for Connecticut are above. Planting windows appear for states with a cited extension guide. The fall and seed tools use the numbers you enter and the station dates.

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