Frost Dates for 48609 — Saginaw, Michigan

Half of springs at Saginaw #3, MI see their last 32°F night by April 29; only one in ten is past it by April 14, and one in ten still has one after May 13. Planting tender crops after May 4 leaves a 30% risk of a frost on them, after May 7 20%, and after May 13 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 80% of the 172 Michigan 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 5 one year in ten, and holds off past November 2 one year in ten. A hard freeze of 28°F follows 13 days later, around November 3; in spring the one-in-ten date for 28°F is May 1, 12 days before the 32°F one. The freeze-free season lasts 175 days in a typical year, longer than at 87% of the 172 Michigan stations; it reaches 194 days one year in ten and falls short of 155 one year in ten. On average 143 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 8 days longer, to about May 7, and return around October 9. Severe cold of 16°F or below comes every winter, usually between December 3 and March 18.

July is the warmest month at Saginaw #3, MI, averaging 83°F by day and 62°F at night; January is the coldest at 30°F and 16°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 39% of years.

Warmth for growing adds up to 2,779 growing degree days a year (base 50°F), more than at 83% of the 172 Michigan stations. 33% of them (904) have built up by the end of June, and July adds the most, 691. Precipitation totals 34.0 inches a year, most in April (3.6") and least in February (1.9"); May to September bring 49% of it.

The nearest other station, Saginaw Mbs International Airport, MI, 9 miles north of Saginaw, has a last frost 3 days earlier (April 26), a first frost 4 days earlier (October 17), a season 3 days shorter.

The first measurable snow (0.1 inch or more) in Saginaw usually arrives around November 30, and the last of the season around March 30. Those are the middle dates across the winters of 1991–2020 at Saginaw #3, MI, 7 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 30 days after the last snow.

ZIP 48609 is 7 miles from Saginaw #3, MI, which stands at 600 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 48601 (Saginaw). The 2023 USDA Plant Hardiness Zone Map lists ZIP 48609 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.