Weston climate

Weston Frost Dates and Growing Season

NOAA 1991-2020 normals for Milton Freewater, 14.4 km from Weston, elevation 970 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Milton Freewater. 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 March 25 and the first fall freeze around October 29, a growing season of about 218 days.

Median at 36°F
last April 19, first October 17
Median at 32°F
last March 25, first October 29
Median at 28°F
last March 5, first November 11

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 8May 2Apr 28Apr 23Apr 19Apr 13Apr 8Apr 4Mar 29
32°FApr 16Apr 8Apr 3Mar 30Mar 25Mar 21Mar 16Mar 11Mar 6
28°FMar 28Mar 21Mar 14Mar 9Mar 5Mar 3Feb 28Feb 24Feb 17
24°FMar 11Mar 4Feb 28Feb 25Feb 21Feb 17Feb 11Feb 3Jan 22
20°FMar 1Feb 24Feb 19Feb 13Feb 7Jan 31Jan 22Jan 13Jan 1
16°FFeb 26Feb 16Feb 8Feb 2Jan 27Jan 18Jan 10Jan 2Dec 18

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°FOct 2Oct 7Oct 12Oct 15Oct 17Oct 20Oct 23Oct 27Nov 2
32°FOct 12Oct 18Oct 22Oct 26Oct 29Nov 1Nov 5Nov 10Nov 16
28°FOct 24Oct 31Nov 3Nov 7Nov 11Nov 15Nov 20Nov 24Dec 1
24°FNov 2Nov 8Nov 13Nov 20Nov 24Nov 28Dec 3Dec 9Dec 17
20°FNov 9Nov 18Nov 25Nov 29Dec 5Dec 10Dec 18Dec 26Jan 7
16°FNov 15Nov 26Dec 2Dec 9Dec 16Dec 23Jan 1Jan 10Jan 29

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°F211201194188182178172166158
32°F243235229223218212206200191
28°F276266258253247242236229217
24°F313301290282275270263255245
20°F345332323314306297288279268
16°F365358346338331323315306291

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
98% of years
16°F or colder
86% 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
4,472
Cooling degree days, base 65°F
1,027
Growing degree days, base 40°F
6,179
Growing degree days, base 45°F
4,747
Growing degree days, base 50°F
3,513
Growing degree days, base 55°F
2,498
Growing degree days, base 60°F
1,675

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January86007
February680013
March524053
April3295149
May14653373
June39137548
July2367829
August4338800
September54117513
October31910191
November641032
December87407

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 14.4 km from Weston. 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 USC00355593 (Milton Freewater). Public domain.