Frost Dates for 52003 — Dubuque, Iowa

Half of springs at Dubuque Regional Airport, IA see their last 32°F night by April 28; only one in ten is past it by April 13, and one in ten still has one after May 12. Planting tender crops after May 4 leaves a 30% risk of a frost on them, after May 7 20%, and after May 12 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 28 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 3, 9 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 186 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 7, and return around October 2. Severe cold of 16°F or below comes every winter, usually between November 19 and March 17.

July is the warmest month at Dubuque Regional Airport, IA, averaging 82°F by day and 62°F at night; January is the coldest at 27°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 42% of years.

Warmth for growing adds up to 2,745 growing degree days a year (base 50°F), fewer than at 83% of the 132 Iowa stations. 34% of them (947) have built up by the end of June, and July adds the most, 674. Precipitation totals 38.3 inches a year, most in June (5.2") and least in January (1.3"); May to September bring 58% of it.

The nearest other station, Dubuque L&D 11, IA, 6 miles north of Dubuque and 436 feet lower, has a last frost 9 days earlier (April 19), a first frost 10 days later (October 21), a season 19 days longer.

The first measurable snow (0.1 inch or more) in Dubuque 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 Dubuque Regional Airport, IA, 4.4 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 18 days after the last snow.

ZIP 52003 is 4 miles from Dubuque Regional Airport, IA, which stands at 1,056 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 52003 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.