Tilden climate

Tilden Frost Dates and Growing Season

NOAA 1991-2020 normals for Tilden 4 Sse, 5.9 km from Tilden, elevation 345 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Tilden 4 Sse. 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 February 13 and the first fall freeze around December 3, a growing season of about 299 days.

Median at 36°F
last March 2, first November 22
Median at 32°F
last February 13, first December 3
Median at 28°F
last January 21, first December 17

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°FMar 27Mar 17Mar 11Mar 6Mar 2Feb 27Feb 21Feb 13Feb 1
32°FMar 11Mar 4Feb 28Feb 21Feb 13Feb 6Jan 30Jan 21Jan 8
28°FMar 2Feb 18Feb 7Jan 31Jan 21Jan 13Jan 3Dec 26Dec 9
24°FFeb 17Feb 2Jan 21Jan 13Jan 5Dec 31Dec 24Dec 15Dec 6
20°FJan 21Jan 13Jan 8Jan 3Dec 29Dec 25Dec 16Dec 11Dec 8
16°F–––––––––

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°FNov 5Nov 10Nov 14Nov 18Nov 22Nov 26Dec 1Dec 6Dec 14
32°FNov 13Nov 19Nov 24Nov 29Dec 3Dec 8Dec 15Dec 26Jan 6
28°FNov 21Nov 28Dec 4Dec 9Dec 17Dec 25Jan 1Jan 12Feb 2
24°FDec 1Dec 8Dec 14Dec 19Dec 26Jan 1Jan 7Jan 20Feb 5
20°FDec 8Dec 11Dec 15Dec 23Dec 28Jan 1Jan 5Jan 9Jan 18
16°F–––––––––

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°F302288278272265260254247239
32°F338324315306299290283273261
28°F365365351342335328319308294
24°F365365365365365365354343329
20°F365365365365365365365365359
16°F365365365365365365365365365

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
99% of years
28°F or colder
83% of years
24°F or colder
42% of years
20°F or colder
14% of years
16°F or colder
3% 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
1,106
Cooling degree days, base 65°F
3,616
Growing degree days, base 40°F
11,647
Growing degree days, base 45°F
9,855
Growing degree days, base 50°F
8,118
Growing degree days, base 55°F
6,480
Growing degree days, base 60°F
4,968

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January33115199
February19639283
March98112486
April21235665
May2439902
June05731,023
July06431,108
August06651,130
September1488938
October23291734
November13489417
December30127233

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 5.9 km from Tilden. 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 USC00419031 (Tilden 4 Sse). Public domain.