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USDA Hardiness Zone 6a

Frost Dates for 48421 — Columbiaville, Michigan

NOAA 1991–2020 normals from Lapeer 2W, MI (837 ft), 7 miles south.

Updated

In Columbiaville, the last spring frost (32°F) is around May 4 in half of years and has passed by May 21 in nine years out of ten. The first fall frost comes around October 13, as early as September 30 one year in ten, leaving a typical freeze-free season of 161 days (NOAA, Lapeer 2W, MI).

Last spring frost
May 4

50% probability

First fall frost
October 13

50% probability

Growing season
161 days

freeze-free, 50%

Hardiness zone
6a

-10 to -5°F (-23.3 to -20.6°C) coldest night

First snow
November 29

median, 1991–2020

Last snow
March 30

median, 1991–2020

Winters with snow
100%

23 of 23 observed

Snow per year
34.4"

NOAA normal

Frost risk by date in Columbiaville

Half of springs at Lapeer 2W, MI see their last 32°F night by May 4; only one in ten is past it by April 21, and one in ten still has one after May 21. Planting tender crops after May 11 leaves a 30% risk of a frost on them, after May 15 20%, and after May 21 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 62% of the 172 Michigan stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 13 in half of years, as early as September 30 one year in ten, and holds off past October 29 one year in ten. A hard freeze of 28°F follows 14 days later, around October 27; in spring the one-in-ten date for 28°F is May 11, 10 days before the 32°F one. The freeze-free season lasts 161 days in a typical year, longer than at 56% of the 172 Michigan stations; it reaches 181 days one year in ten and falls short of 138 one year in ten. On average 138 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 May 14, and return around October 2. Severe cold of 16°F or below comes every winter, usually between December 2 and March 21.

Spring: the chance of another night this cold after the date
Low90%80%70%60%50%40%30%20%10%
36°FApr 30May 4May 7May 11May 14May 18May 21May 25May 28
32°FApr 21Apr 25Apr 29May 1May 4May 7May 11May 15May 21
28°FApr 9Apr 15Apr 18Apr 21Apr 24Apr 27Apr 30May 5May 11
24°FMar 28Apr 2Apr 5Apr 9Apr 13Apr 16Apr 18Apr 22Apr 29
20°FMar 14Mar 19Mar 25Mar 29Mar 31Apr 2Apr 5Apr 9Apr 16
16°FMar 4Mar 10Mar 14Mar 17Mar 21Mar 24Mar 28Mar 31Apr 4
Fall: the chance the first night this cold has come by the date
Low10%20%30%40%50%60%70%80%90%
36°FSep 19Sep 24Sep 28Oct 1Oct 2Oct 5Oct 8Oct 11Oct 15
32°FSep 30Oct 3Oct 7Oct 11Oct 13Oct 16Oct 20Oct 24Oct 29
28°FOct 12Oct 17Oct 21Oct 24Oct 27Oct 31Nov 2Nov 6Nov 11
24°FOct 25Oct 31Nov 2Nov 6Nov 8Nov 11Nov 16Nov 21Nov 26
20°FNov 6Nov 11Nov 15Nov 19Nov 22Nov 26Nov 29Dec 3Dec 9
16°FNov 15Nov 22Nov 26Nov 29Dec 2Dec 5Dec 9Dec 13Dec 19

Freeze probabilities 1991–2020 at Lapeer 2W, MI, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.

Frost risk on any date in 48421 →Compare Columbiaville with another place →

Weather by month in Columbiaville

July is the warmest month at Lapeer 2W, MI, averaging 82°F by day and 61°F at night; January is the coldest at 31°F and 16°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 62% of years.

Warmth for growing adds up to 2,681 growing degree days a year (base 50°F), more than at 71% of the 172 Michigan stations. 33% of them (881) have built up by the end of June, and July adds the most, 666. Precipitation totals 36.3 inches a year, most in August (4.6") and least in February (2.3"); May to September bring 48% of it.

Monthly normals 1991–2020 at Lapeer 2W, MI
MonthHigh °FLow °FPrecip. in32°F nightNights ≤ 32°FGDD 50°F
Jan31162.8100%290
Feb35162.3100%261
Mar45252.5100%2320
Apr57353.3100%1270
May69463.762%1271
Jun78573.20%0518
Jul82613.40%0666
Aug80594.60%0606
Sep74512.612%<1381
Oct61403.091%5122
Nov48322.6100%1723
Dec36232.3100%261

Monthly normals 1991–2020 at Lapeer 2W, MI (837 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.

Compared with the next station

The nearest other station, Lapeer Wwtp, MI, 8 miles southeast of Columbiaville, has the same 50% last-frost date, a first frost 1 day later (October 14), a season 1 day shorter.

Frost dates for 48446 (Lapeer) →

When it snows in Columbiaville, Michigan

The first measurable snow (0.1 inch or more) in Columbiaville usually arrives around November 29, and the last of the season around March 30. Those are the middle dates across the winters of 1991–2020 at Lapeer Wwtp, MI, 7.8 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.

Planting calendar for 48421

What to do and when, from the 50% frost dates for Columbiaville, Michigan
WhenWhat to do
February 23 – March 9Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out.
March 9 – March 23Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early.
April 6 – April 20Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil.
May 4 onwardTransplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast.
by July 21Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops.
by September 29Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation.
October 13 onwardPlant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter.

The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.

Where these figures come from

ZIP 48421 is 7 miles from Lapeer 2W, MI, which stands at 837 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 48421 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.

Frost dates across Michigan →

Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.

Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.

ZIP codes measured at the same station

Other zone 6a places in Michigan