Flint climate

Flint Frost Dates and Growing Season

NOAA 1991-2020 normals for Flint Bishop Intl AP, 7.2 km from Flint, elevation 770 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Flint Bishop Intl AP. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

The last spring freeze typically comes around May 6 and the first fall freeze around October 10, a growing season of about 155 days.

Median at 36°F
last May 18, first September 28
Median at 32°F
last May 6, first October 10
Median at 28°F
last April 26, first October 23

Last freeze in spring

The chance of a later freeze than the date shown. At 10 percent, one spring in ten still freezes after the date; planting after the 10 percent date for 32°F is the cautious choice.

Threshold10%20%30%40%50%60%70%80%90%
36°FJun 2May 29May 25May 22May 18May 15May 11May 7May 2
32°FMay 23May 18May 13May 9May 6May 3Apr 30Apr 26Apr 21
28°FMay 13May 6May 2Apr 29Apr 26Apr 23Apr 19Apr 16Apr 11
24°FMay 1Apr 24Apr 20Apr 17Apr 14Apr 10Apr 7Apr 3Mar 30
20°FApr 16Apr 10Apr 5Apr 3Apr 1Mar 29Mar 26Mar 21Mar 15
16°FApr 3Mar 30Mar 27Mar 23Mar 20Mar 17Mar 14Mar 10Mar 6

First freeze in fall

The chance of an earlier freeze than the date shown. At 10 percent, one fall in ten freezes before the date.

Threshold10%20%30%40%50%60%70%80%90%
36°FSep 15Sep 20Sep 23Sep 26Sep 28Oct 1Oct 3Oct 5Oct 10
32°FSep 26Oct 1Oct 4Oct 6Oct 10Oct 12Oct 15Oct 20Oct 25
28°FOct 6Oct 12Oct 17Oct 20Oct 23Oct 28Oct 30Nov 2Nov 6
24°FOct 20Oct 27Oct 31Nov 2Nov 4Nov 6Nov 9Nov 14Nov 20
20°FNov 2Nov 5Nov 9Nov 12Nov 15Nov 19Nov 22Nov 27Dec 2
16°FNov 9Nov 15Nov 20Nov 24Nov 28Dec 1Dec 4Dec 9Dec 17

Growing season length

Days between the last spring and first fall freeze at each threshold, with the chance of a season at least that long.

Threshold10%20%30%40%50%60%70%80%90%
36°F152146141137132128124120113
32°F177170164159155152147142133
28°F200194188184179175170164156
24°F228219214209205201196191182
20°F254246241235231226221217209
16°F277268261256252247243237229

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
100% of years
32°F or colder
100% of years
28°F or colder
100% of years
24°F or colder
100% of years
20°F or colder
100% of years
16°F or colder
100% of years

Degree days

A degree day is one degree of the daily mean temperature beyond a base, for one day. Heating degree days count cold (the fuel a house burns), cooling degree days heat, growing degree days the warmth a crop needs; each crop has its own base.

Heating degree days, base 65°F
6,851
Cooling degree days, base 65°F
565
Growing degree days, base 40°F
4,611
Growing degree days, base 45°F
3,529
Growing degree days, base 50°F
2,586
Growing degree days, base 55°F
1,773
Growing degree days, base 60°F
1,091

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,30300
February1,12701
March956116
April572264
May26834258
June58119512
July13196648
August25152592
September15255360
October4656115
November786020
December1,12502

What this means

NOAA computes these from the daily lows at the station over 1991-2020, fitting the dates of each year's last and first freeze to a distribution, so a date can be stated at any level of risk. 36°F is a frost risk for tender plants on a clear, calm night, since the ground cools below the air above it; 32°F is a freeze; 28°F is a hard freeze that kills most annuals.

The station is 7.2 km from Flint. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USW00014826 (Flint Bishop Intl AP). Public domain.