Lancaster climate

Lancaster Frost Dates and Growing Season

NOAA 1991-2020 normals for Warsaw 2 Nw, 36.5 km from Lancaster, elevation 140 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Warsaw 2 Nw. 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 8 and the first fall freeze around October 30, a growing season of about 204 days.

Median at 36°F
last April 22, first October 20
Median at 32°F
last April 8, first October 30
Median at 28°F
last March 29, first November 10

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 7May 2Apr 29Apr 25Apr 22Apr 19Apr 15Apr 12Apr 7
32°FApr 23Apr 18Apr 14Apr 11Apr 8Apr 5Apr 3Mar 31Mar 26
28°FApr 10Apr 5Apr 2Mar 31Mar 29Mar 26Mar 23Mar 19Mar 12
24°FMar 31Mar 27Mar 23Mar 19Mar 17Mar 13Mar 8Mar 1Feb 25
20°FMar 21Mar 16Mar 11Mar 7Mar 2Feb 28Feb 24Feb 17Feb 8
16°FMar 12Mar 5Feb 28Feb 25Feb 18Feb 11Feb 5Jan 31Jan 20

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 7Oct 11Oct 14Oct 17Oct 20Oct 23Oct 26Oct 29Nov 1
32°FOct 15Oct 21Oct 24Oct 27Oct 30Nov 1Nov 4Nov 7Nov 12
28°FOct 28Nov 1Nov 4Nov 6Nov 10Nov 13Nov 17Nov 21Nov 28
24°FNov 6Nov 11Nov 16Nov 20Nov 24Nov 29Dec 2Dec 7Dec 15
20°FNov 17Nov 25Dec 1Dec 4Dec 9Dec 15Dec 21Dec 26Jan 4
16°FDec 3Dec 11Dec 20Dec 25Dec 30Jan 2Jan 8Jan 14Jan 22

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°F199193189184180177172167161
32°F223216212208204200195191183
28°F250243237232227223219215208
24°F280271264259253249244238230
20°F309301294288283277270264255
16°F340329323315308304298291281

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
98% 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
3,880
Cooling degree days, base 65°F
1,417
Growing degree days, base 40°F
7,081
Growing degree days, base 45°F
5,640
Growing degree days, base 50°F
4,351
Growing degree days, base 55°F
3,216
Growing degree days, base 60°F
2,238

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January848020
February692025
March547591
April25234261
May79116503
June8275717
July0411876
August1349814
September29182603
October21039308
November4754103
December740131

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 36.5 km from Lancaster. 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 USC00448894 (Warsaw 2 Nw). Public domain.