Frost Dates for 66012 — Bonner Springs, Kansas

Half of springs at Bonner Springs, 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 23 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 22 in half of years, as early as October 9 one year in ten, and holds off past November 2 one year in ten. A hard freeze of 28°F follows 9 days later, around October 31; in spring the one-in-ten date for 28°F is April 22, 9 days before the 32°F one. The freeze-free season lasts 188 days in a typical year, shorter than at 48% of the 110 Kansas stations; it reaches 208 days one year in ten and falls short of 167 one year in ten. On average 128 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 April 28, and return around October 13. Severe cold of 16°F or below comes every winter, usually between November 30 and March 4.

July is the warmest month at Bonner Springs, KS, averaging 87°F by day and 67°F at night; January is the coldest at 38°F and 18°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 10% of years.

Warmth for growing adds up to 3,769 growing degree days a year (base 50°F), fewer than at 86% of the 110 Kansas stations. 36% of them (1,349) have built up by the end of June, and July adds the most, 846. Precipitation totals 40.5 inches a year, most in June (5.5") and least in January (1.2"); May to September bring 59% of it.

The nearest other station, Olathe 3E, KS, 15 miles southeast of Bonner Springs and 205 feet higher, has a last frost 6 days earlier (April 10), a first frost 7 days later (October 29), a season 14 days longer.

The first measurable snow (0.1 inch or more) in Bonner Springs usually arrives around December 3, and the last of the season around March 12. Those are the middle dates across the winters of 1991–2020 at Bonner Springs, KS, 0.5 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 35 days after the last snow.

ZIP 66012 is under a mile from Bonner Springs, KS, which stands at 850 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 9 other ZIP codes share the station; its figures are presented in full for 66109 (Kansas City). The 2023 USDA Plant Hardiness Zone Map lists ZIP 66012 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.