Frost Dates for 66506 — Manhattan, Kansas

Half of springs at Manhattan, KS see their last 32°F night by April 16; only one in ten is past it by April 1, and one in ten still has one after May 1. Planting tender crops after April 22 leaves a 30% risk of a frost on them, after April 26 20%, and after May 1 10%. The 15 days between the even-odds date and the one-in-ten date is wider than at 57% of the 110 Kansas stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 19 in half of years, as early as October 1 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 10 days later, around October 29; in spring the one-in-ten date for 28°F is April 24, 7 days before the 32°F one. The freeze-free season lasts 185 days in a typical year, shorter than at 58% of the 110 Kansas stations; it reaches 205 days one year in ten and falls short of 163 one year in ten. On average 125 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 11 days longer, to about April 27, and return around October 9. Severe cold of 16°F or below comes every winter, usually between November 28 and March 8.

July is the warmest month at Manhattan, KS, averaging 91°F by day and 69°F at night; January is the coldest at 40°F and 19°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 11% of years.

Warmth for growing adds up to 4,172 growing degree days a year (base 50°F), more than at 59% of the 110 Kansas stations. 36% of them (1,497) have built up by the end of June, and July adds the most, 931. Precipitation totals 35.7 inches a year, most in June (5.5") and least in January (0.6"); May to September bring 65% of it.

The nearest other station, Tuttle Creek Lake, KS, 4 miles north of Manhattan, has a last frost 6 days later (April 22), a first frost 1 day later (October 20), a season 6 days shorter.

The first measurable snow (0.1 inch or more) in Manhattan usually arrives around December 8, and the last of the season around March 6. Those are the middle dates across the winters of 1991–2020 at Manhattan, KS, 0.3 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 41 days after the last snow.

ZIP 66506 is under a mile from Manhattan, KS, which stands at 1,060 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 66502 (Manhattan). The 2023 USDA Plant Hardiness Zone Map lists ZIP 66506 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°C) over 1991–2020; a zone describes winter lows, not frost dates.