Frost Dates for 52228 — Fairfax, Iowa

Half of springs at Cedar Rapids Municipal Airport, IA see their last 32°F night by April 27; only one in ten is past it by April 13, and one in ten still has one after May 11. Planting tender crops after May 3 leaves a 30% risk of a frost on them, after May 6 20%, and after May 11 10%. The 14 days between the even-odds date and the one-in-ten date is wider than at 58% of the 132 Iowa stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 11 in half of years, as early as September 25 one year in ten, and holds off past October 23 one year in ten. A hard freeze of 28°F follows 10 days later, around October 21; in spring the one-in-ten date for 28°F is May 1, 10 days before the 32°F one. The freeze-free season lasts 165 days in a typical year, shorter than at 45% of the 132 Iowa stations; it reaches 184 days one year in ten and falls short of 146 one year in ten. On average 144 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 9 days longer, to about May 6, and return around October 1. Severe cold of 16°F or below comes every winter, usually between November 16 and March 18.

July is the warmest month at Cedar Rapids Municipal Airport, IA, averaging 83°F by day and 63°F at night; January is the coldest at 28°F and 11°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 37% of years.

Warmth for growing adds up to 2,962 growing degree days a year (base 50°F), fewer than at 57% of the 132 Iowa stations. 36% of them (1,053) have built up by the end of June, and July adds the most, 705. Precipitation totals 36.1 inches a year, most in June (5.6") and least in January (1.0"); May to September bring 60% of it.

The nearest other station, Cedar Rapids #1, IA, 14 miles northeast of Fairfax, has a last frost 1 day later (April 28), a first frost 1 day later (October 12), a season 1 day longer.

The first measurable snow (0.1 inch or more) in Fairfax usually arrives around December 1, and the last of the season around March 19. Those are the middle dates across the winters of 1991–2020 at Walford 2 SE, IA, 3.5 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 39 days after the last snow.

ZIP 52228 is 4 miles from Cedar Rapids Municipal Airport, IA, which stands at 868 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 7 other ZIP codes share the station; its figures are presented in full for 52404 (Cedar Rapids). The 2023 USDA Plant Hardiness Zone Map lists ZIP 52228 in zone 5a, the band where the coldest night of the year averaged -20 to -15°F (-28.9 to -26.1°C) over 1991–2020; a zone describes winter lows, not frost dates.