Frost Dates for 03598 — Whitefield, New Hampshire

Half of springs at Whitefield Mt Washington Airport, NH see their last 32°F night by May 27; only one in ten is past it by May 11, and one in ten still has one after June 10. Planting tender crops after June 2 leaves a 30% risk of a frost on them, after June 5 20%, and after June 10 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 25% of the 51 New Hampshire stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 19 in half of years, as early as September 8 one year in ten, and holds off past October 3 one year in ten. A hard freeze of 28°F follows 13 days later, around October 2; in spring the one-in-ten date for 28°F is May 27, 14 days before the 32°F one. The freeze-free season lasts 116 days in a typical year, shorter than at 96% of the 51 New Hampshire stations; it reaches 135 days one year in ten and falls short of 97 one year in ten. On average 194 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 12 days longer, to about June 8, and return around September 8. Severe cold of 16°F or below comes every winter, usually between November 11 and April 4.

July is the warmest month at Whitefield Mt Washington Airport, NH, averaging 80°F by day and 53°F at night; January is the coldest at 27°F and 5°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 34% of years.

Warmth for growing adds up to 1,805 growing degree days a year (base 50°F), fewer than at 86% of the 51 New Hampshire stations. 30% of them (540) have built up by the end of June, and July adds the most, 516. Precipitation totals 37.1 inches a year, most in July (4.5") and least in February (1.5"); May to September bring 53% of it.

The nearest other station, Bethlehem 2, NH, 5 miles south of Whitefield, has a last frost 3 days earlier (May 24), a first frost 1 day earlier (September 18).

The first measurable snow (0.1 inch or more) in Whitefield usually arrives around November 15, and the last of the season around April 12. Those are the middle dates across the winters of 1991–2020 at Gilman, VT, 5.2 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 45 days after the last snow.

ZIP 03598 is 4 miles from Whitefield Mt Washington Airport, NH, which stands at 1,074 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 03598 in zone 4b, the band where the coldest night of the year averaged -25 to -20°F (-31.7 to -28.9°C) over 1991–2020; a zone describes winter lows, not frost dates.