Lancaster climate

Lancaster Frost Dates and Growing Season

NOAA 1991-2020 normals for Lancaster 2NE Fltr Plt, 2.9 km from Lancaster, elevation 270 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lancaster 2NE Fltr Plt. 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 19 and the first fall freeze around October 24, a growing season of about 186 days.

Median at 36°F
last May 2, first October 13
Median at 32°F
last April 19, first October 24
Median at 28°F
last April 5, first November 4

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 20May 14May 9May 5May 2Apr 30Apr 26Apr 23Apr 19
32°FMay 7May 2Apr 27Apr 22Apr 19Apr 17Apr 14Apr 10Apr 5
28°FApr 24Apr 17Apr 12Apr 8Apr 5Apr 2Mar 31Mar 28Mar 22
24°FApr 5Apr 1Mar 30Mar 27Mar 24Mar 21Mar 17Mar 13Mar 8
20°FMar 26Mar 22Mar 18Mar 15Mar 12Mar 9Mar 5Mar 2Feb 25
16°FMar 18Mar 13Mar 9Mar 5Mar 2Feb 27Feb 22Feb 16Feb 10

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 5Oct 8Oct 11Oct 13Oct 16Oct 19Oct 22Oct 27
32°FOct 9Oct 15Oct 17Oct 21Oct 24Oct 27Oct 30Nov 2Nov 6
28°FOct 20Oct 26Oct 30Nov 1Nov 4Nov 6Nov 10Nov 14Nov 20
24°FNov 3Nov 8Nov 12Nov 15Nov 18Nov 21Nov 25Nov 30Dec 5
20°FNov 16Nov 20Nov 25Nov 29Dec 2Dec 6Dec 10Dec 15Dec 23
16°FNov 29Dec 5Dec 10Dec 14Dec 20Dec 24Dec 28Jan 1Jan 9

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°F183177172169165160157151144
32°F205199195190186182178172163
28°F234227222217212209204198189
24°F264255249245240236232227219
20°F291282276271266260255250243
16°F316308303297292287282277268

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
5,129
Cooling degree days, base 65°F
1,030
Growing degree days, base 40°F
5,877
Growing degree days, base 45°F
4,613
Growing degree days, base 50°F
3,496
Growing degree days, base 55°F
2,532
Growing degree days, base 60°F
1,707

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,05203
February89004
March731128
April38310143
May14464389
June18204636
July0337801
August2283746
September61118508
October32315193
November618039
December90707

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 2.9 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 USC00364763 (Lancaster 2NE Fltr Plt). Public domain.