Frost dates / New Hampshire / Concord

Frost dates in Concord, NH

The station on this page is CONCORD MUNI AP, NH US (USW00014745), 4 miles from the city point. Population in the Census 2024 estimate is 44,674.

Zone 5bUSDA average annual extreme minimum -15°F to -10°F, from ZIP 03301 (0.5 miles from the city point used on this page).

Median last 32°F is May 8. Median first 32°F is October 3. The 50% growing-season length is 146 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 27	Earlier date. A last 32°F on or after this day is common.
50%	May 8	Median.
10%	May 22	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%	September 21	Earlier date. A first 32°F on or before this day is uncommon.
50%	October 3	Median.
90%	October 16	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%	163
50%	146
90%	128

28°F threshold

	10%	50%	90%
Last, on or after	May 9	April 27	April 15
First, on or before	October 1	October 13	October 30
Season at least	188 days	169 days	151 days

36°F threshold

	10%	50%	90%
Last, on or after	June 3	May 20	May 7
First, on or before	September 9	September 23	October 5
Season at least	143 days	124 days	106 days

Station CONCORD MUNI AP, NH US (USW00014745). Completeness flag S, 30 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 105.5 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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Concord, NH

Zone 5bAverage annual extreme minimum -15°F to -10°F

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

New Hampshire. Nearest qualified station: CONCORD MUNI AP, NH US (USW00014745), 4 miles. Median last 32°F May 8. Median first 32°F October 3. The 50% growing-season length is 146 days.

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32°F probabilities at this station

	10%	50%	90%
Last 32°F on or after	May 22	May 8	April 27
First 32°F on or before	September 21	October 3	October 16

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 New Hampshire 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.

Date checks use your device’s calendar and appear after the page loads.