Frost Dates for 03570 — Berlin, New Hampshire

Half of springs at Berlin, NH see their last 32°F night by May 14; only one in ten is past it by April 30, and one in ten still has one after May 30. Planting tender crops after May 20 leaves a 30% risk of a frost on them, after May 25 20%, and after May 30 10%. The 16 days between the even-odds date and the one-in-ten date is wider than at 94% of the 51 New Hampshire stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 30 in half of years, as early as September 15 one year in ten, and holds off past October 11 one year in ten. A hard freeze of 28°F follows 10 days later, around October 10; in spring the one-in-ten date for 28°F is May 14, 16 days before the 32°F one. The freeze-free season lasts 135 days in a typical year, shorter than at 76% of the 51 New Hampshire stations; it reaches 154 days one year in ten and falls short of 117 one year in ten. On average 174 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 15 days longer, to about May 29, and return around September 18. Severe cold of 16°F or below comes every winter, usually between November 18 and April 2.

July is the warmest month at Berlin, NH, averaging 78°F by day and 55°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 April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 90% of years.

Warmth for growing adds up to 1,804 growing degree days a year (base 50°F), fewer than at 88% of the 51 New Hampshire stations. 30% of them (538) have built up by the end of June, and July adds the most, 513. Precipitation totals 42.6 inches a year, most in October (4.9") and least in February (2.4"); May to September bring 45% of it.

The nearest other station, Gorham Airport, NH, 5 miles south of Berlin, has the same 50% last-frost date, a first frost 4 days earlier (September 26), a season 2 days shorter.

The first measurable snow (0.1 inch or more) in Berlin usually arrives around November 12, and the last of the season around April 10. Those are the middle dates across the winters of 1991–2020 at Berlin, NH, 0.7 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 34 days after the last snow.

ZIP 03570 is under a mile from Berlin, NH, which stands at 920 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 03570 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.