Preston climate

Preston Frost Dates and Growing Season

NOAA 1991-2020 normals for Royal Oak 2 Ssw, 24.4 km from Preston, elevation 10 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Royal Oak 2 Ssw. 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 1 and the first fall freeze around November 7, a growing season of about 220 days.

Median at 36°F
last April 15, first October 29
Median at 32°F
last April 1, first November 7
Median at 28°F
last March 20, first November 20

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 3Apr 25Apr 21Apr 18Apr 15Apr 11Apr 8Apr 4Mar 31
32°FApr 15Apr 10Apr 7Apr 4Apr 1Mar 30Mar 27Mar 23Mar 18
28°FApr 1Mar 29Mar 26Mar 22Mar 20Mar 17Mar 14Mar 10Mar 3
24°FMar 23Mar 19Mar 16Mar 12Mar 8Mar 5Mar 1Feb 26Feb 19
20°FMar 15Mar 9Mar 3Feb 28Feb 25Feb 20Feb 15Feb 9Jan 31
16°FMar 3Feb 26Feb 20Feb 13Feb 8Feb 3Jan 30Jan 24Jan 13

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 11Oct 17Oct 22Oct 25Oct 29Oct 31Nov 2Nov 5Nov 10
32°FOct 24Oct 30Nov 2Nov 5Nov 7Nov 10Nov 13Nov 17Nov 23
28°FNov 5Nov 9Nov 13Nov 16Nov 20Nov 24Nov 28Dec 3Dec 9
24°FNov 17Nov 24Nov 29Dec 2Dec 6Dec 10Dec 15Dec 20Dec 27
20°FDec 3Dec 9Dec 15Dec 20Dec 25Dec 29Jan 1Jan 7Jan 15
16°FDec 15Dec 24Dec 30Jan 2Jan 8Jan 13Jan 18Jan 24Feb 4

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°F216209204199196191187182173
32°F240233229224220216212208202
28°F269260254250246241237231224
24°F299290284278273268263258248
20°F327318311306301296290283276
16°F362347336332325318311306296

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
99% of years
16°F or colder
91% 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
3,972
Cooling degree days, base 65°F
1,473
Growing degree days, base 40°F
7,045
Growing degree days, base 45°F
5,613
Growing degree days, base 50°F
4,342
Growing degree days, base 55°F
3,230
Growing degree days, base 60°F
2,276

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January870012
February729013
March578265
April26922229
May81106490
June6294738
July0437902
August0377842
September23197624
October19837313
November472292
December746022

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 24.4 km from Preston. 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 USC00187806 (Royal Oak 2 Ssw). Public domain.