Lancaster climate

Lancaster Frost Dates and Growing Season

NOAA 1991-2020 normals for Lancaster, 0.7 km from Lancaster, elevation 827 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lancaster. 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 22 and the first fall freeze around October 24, a growing season of about 183 days.

Median at 36°F
last May 1, first October 12
Median at 32°F
last April 22, first October 24
Median at 28°F
last April 8, first November 3

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 7May 4May 1Apr 29Apr 25Apr 22Apr 18
32°FMay 9May 3Apr 30Apr 26Apr 22Apr 19Apr 16Apr 13Apr 7
28°FApr 27Apr 20Apr 16Apr 12Apr 8Apr 5Apr 2Mar 30Mar 24
24°FApr 14Apr 7Apr 3Apr 1Mar 29Mar 26Mar 22Mar 18Mar 12
20°FApr 3Mar 28Mar 24Mar 21Mar 18Mar 14Mar 10Mar 6Feb 28
16°FMar 24Mar 18Mar 13Mar 9Mar 5Mar 2Feb 28Feb 22Feb 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°FSep 27Oct 3Oct 6Oct 9Oct 12Oct 15Oct 18Oct 21Oct 26
32°FOct 8Oct 14Oct 18Oct 21Oct 24Oct 26Oct 29Nov 2Nov 6
28°FOct 19Oct 24Oct 29Nov 1Nov 3Nov 5Nov 8Nov 12Nov 17
24°FOct 29Nov 4Nov 7Nov 10Nov 13Nov 17Nov 21Nov 27Dec 2
20°FNov 8Nov 13Nov 19Nov 24Nov 28Dec 1Dec 4Dec 9Dec 18
16°FNov 21Nov 29Dec 3Dec 6Dec 11Dec 15Dec 20Dec 25Jan 1

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°F181175170164161157152148141
32°F204196191187183179174168161
28°F228220215210207202198192184
24°F256247241236230226221215208
20°F283272265259254249244237228
16°F307298291285279273267260250

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
5,274
Cooling degree days, base 65°F
1,003
Growing degree days, base 40°F
5,895
Growing degree days, base 45°F
4,635
Growing degree days, base 50°F
3,518
Growing degree days, base 55°F
2,544
Growing degree days, base 60°F
1,704

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,10006
February90609
March725148
April37313168
May14278409
June16212646
July2307770
August3264725
September67111495
October33717195
November653038
December95009

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 0.7 km from Lancaster. 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 USC00334403 (Lancaster). Public domain.