Frost Dates for 68069 — Waterloo, Nebraska

Half of springs at Valley NWS, NE see their last 32°F night by April 15; only one in ten is past it by April 2, and one in ten still has one after April 29. Planting tender crops after April 21 leaves a 30% risk of a frost on them, after April 24 20%, and after April 29 10%. The 14 days between the even-odds date and the one-in-ten date is wider than at 72% of the 68 Nebraska stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 21 in half of years, as early as October 6 one year in ten, and holds off past November 2 one year in ten. A hard freeze of 28°F follows 10 days later, around October 31; in spring the one-in-ten date for 28°F is April 20, 9 days before the 32°F one. The freeze-free season lasts 187 days in a typical year, the longest of the 68 Nebraska stations; it reaches 206 days one year in ten and falls short of 167 one year in ten. On average 136 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 10 days longer, to about April 25, and return around October 12. Severe cold of 16°F or below comes every winter, usually between November 26 and March 10.

July is the warmest month at Valley NWS, NE, averaging 87°F by day and 68°F at night; January is the coldest at 33°F and 15°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month.

Warmth for growing adds up to 3,660 growing degree days a year (base 50°F), more than at 94% of the 68 Nebraska stations. 36% of them (1,303) have built up by the end of June, and July adds the most, 846. Precipitation totals 33.2 inches a year, most in June (5.3") and least in January (0.9"); May to September bring 64% of it.

The nearest other station, Gretna 4NE, NE, 9 miles southeast of Waterloo, has a last frost 6 days later (April 21), a first frost 3 days earlier (October 18), a season 8 days shorter.

The first measurable snow (0.1 inch or more) in Waterloo usually arrives around November 22, and the last of the season around March 27. Those are the middle dates across the winters of 1991–2020 at Valley NWS, NE, 5.6 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 19 days after the last snow.

ZIP 68069 is 6 miles from Valley NWS, NE, which stands at 1,145 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 68022 (Elkhorn). The 2023 USDA Plant Hardiness Zone Map lists ZIP 68069 in zone 5b, the band where the coldest night of the year averaged -15 to -10°F (-26.1 to -23.3°C) over 1991–2020; a zone describes winter lows, not frost dates.