Ephrata climate

Ephrata Frost Dates and Growing Season

NOAA 1991-2020 normals for New Holland 2 Se, 14.8 km from Ephrata, elevation 605 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for New Holland 2 Se. 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 14 and the first fall freeze around November 1, a growing season of about 198 days.

Median at 36°F
last April 25, first October 20
Median at 32°F
last April 14, first November 1
Median at 28°F
last April 3, first November 11

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 12May 6May 2Apr 30Apr 25Apr 22Apr 20Apr 17Apr 12
32°FApr 30Apr 24Apr 20Apr 17Apr 14Apr 11Apr 8Apr 5Apr 1
28°FApr 17Apr 12Apr 8Apr 5Apr 3Apr 1Mar 30Mar 26Mar 20
24°FApr 4Apr 2Mar 30Mar 27Mar 25Mar 21Mar 18Mar 14Mar 7
20°FMar 27Mar 23Mar 19Mar 16Mar 13Mar 10Mar 7Mar 3Feb 25
16°FMar 19Mar 14Mar 10Mar 7Mar 4Mar 1Feb 26Feb 20Feb 12

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 6Oct 11Oct 14Oct 17Oct 20Oct 23Oct 25Oct 29Nov 2
32°FOct 17Oct 23Oct 26Oct 29Nov 1Nov 3Nov 5Nov 8Nov 13
28°FOct 31Nov 3Nov 6Nov 9Nov 11Nov 14Nov 17Nov 21Nov 28
24°FNov 8Nov 12Nov 16Nov 18Nov 22Nov 26Dec 1Dec 5Dec 11
20°FNov 16Nov 23Nov 28Dec 1Dec 5Dec 9Dec 14Dec 19Dec 26
16°FNov 29Dec 4Dec 10Dec 15Dec 20Dec 25Dec 29Jan 3Jan 11

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°F195189184181177173169164156
32°F217211206202198195190185178
28°F244236230226222218214210204
24°F270261254250245240236230223
20°F294286279274268262257252244
16°F314306300295291285280273264

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
5,067
Cooling degree days, base 65°F
1,085
Growing degree days, base 40°F
6,011
Growing degree days, base 45°F
4,736
Growing degree days, base 50°F
3,607
Growing degree days, base 55°F
2,625
Growing degree days, base 60°F
1,781

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,05105
February89204
March739132
April38213151
May13769399
June17213646
July0344809
August2298761
September55127523
October29519221
November599047
December89909

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 14.8 km from Ephrata. 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 USC00366238 (New Holland 2 Se). Public domain.