Blue Rapids climate

Blue Rapids Frost Dates and Growing Season

NOAA 1991-2020 normals for Marysville, 17.5 km from Blue Rapids, elevation 1178 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Marysville. 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 April 25 and the first fall freeze around October 13, a growing season of about 171 days.

Median at 36°F
last May 3, first October 3
Median at 32°F
last April 25, first October 13
Median at 28°F
last April 14, first October 22

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°FMay 19May 12May 8May 5May 3Apr 30Apr 28Apr 24Apr 20
32°FMay 9May 3Apr 30Apr 28Apr 25Apr 21Apr 18Apr 15Apr 10
28°FApr 30Apr 25Apr 21Apr 17Apr 14Apr 11Apr 8Apr 4Mar 30
24°FApr 21Apr 14Apr 9Apr 6Apr 3Mar 31Mar 28Mar 24Mar 16
20°FApr 10Apr 4Apr 1Mar 28Mar 24Mar 20Mar 16Mar 12Mar 6
16°FApr 1Mar 26Mar 21Mar 16Mar 13Mar 10Mar 6Mar 2Feb 25

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 19Sep 25Sep 29Oct 1Oct 3Oct 6Oct 9Oct 12Oct 17
32°FSep 28Oct 3Oct 7Oct 10Oct 13Oct 16Oct 19Oct 22Oct 26
28°FOct 6Oct 13Oct 16Oct 20Oct 22Oct 25Oct 28Oct 31Nov 4
24°FOct 17Oct 22Oct 26Oct 30Nov 1Nov 4Nov 6Nov 11Nov 16
20°FOct 25Nov 1Nov 4Nov 7Nov 11Nov 14Nov 18Nov 23Nov 28
16°FNov 1Nov 8Nov 13Nov 17Nov 21Nov 25Nov 29Dec 3Dec 7

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°F171164160156152149145140133
32°F191184179175171167163158150
28°F212205200196191187183177170
24°F235227221216212207203198190
20°F256248242237232227222215206
16°F276269262256251246241235225

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
5,522
Cooling degree days, base 65°F
1,355
Growing degree days, base 40°F
6,225
Growing degree days, base 45°F
4,996
Growing degree days, base 50°F
3,897
Growing degree days, base 55°F
2,925
Growing degree days, base 60°F
2,077

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,18600
February94408
March702358
April38116174
May13795430
June13278715
July1419883
August4355817
September73159538
October32827227
November696243
December1,05902

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 17.5 km from Blue Rapids. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00145063 (Marysville). Public domain.