Reading climate

Reading Frost Dates and Growing Season

NOAA 1991-2020 normals for Hillsdale, 13.8 km from Reading, elevation 1080 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hillsdale. 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 May 3 and the first fall freeze around October 12, a growing season of about 161 days.

Median at 36°F
last May 14, first October 1
Median at 32°F
last May 3, first October 12
Median at 28°F
last April 23, first October 26

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 30May 26May 21May 18May 14May 11May 8May 3Apr 30
32°FMay 19May 14May 10May 6May 3Apr 30Apr 28Apr 24Apr 20
28°FMay 9May 3Apr 30Apr 27Apr 23Apr 20Apr 17Apr 13Apr 8
24°FApr 30Apr 21Apr 18Apr 14Apr 11Apr 8Apr 4Apr 2Mar 29
20°FApr 17Apr 11Apr 6Apr 3Apr 1Mar 30Mar 26Mar 22Mar 16
16°FApr 6Apr 1Mar 30Mar 26Mar 22Mar 19Mar 15Mar 12Mar 6

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 18Sep 23Sep 27Sep 30Oct 1Oct 4Oct 6Oct 9Oct 13
32°FSep 29Oct 3Oct 6Oct 10Oct 12Oct 15Oct 19Oct 22Oct 27
28°FOct 10Oct 16Oct 20Oct 23Oct 26Oct 28Oct 31Nov 3Nov 8
24°FOct 24Oct 29Nov 1Nov 3Nov 5Nov 8Nov 12Nov 15Nov 20
20°FNov 3Nov 7Nov 10Nov 14Nov 17Nov 20Nov 25Nov 30Dec 6
16°FNov 12Nov 17Nov 21Nov 26Nov 30Dec 3Dec 6Dec 12Dec 18

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°F159152147143139135131126120
32°F181174169165161156152147140
28°F203196192187184180176170161
24°F229221217212207203199194186
20°F253246239235231226221217210
16°F275266261256251247241235228

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
6,798
Cooling degree days, base 65°F
594
Growing degree days, base 40°F
4,684
Growing degree days, base 45°F
3,600
Growing degree days, base 50°F
2,649
Growing degree days, base 55°F
1,829
Growing degree days, base 60°F
1,137

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,30700
February1,11601
March949114
April564473
May25237276
June54129526
July13205657
August24154595
September14659370
October4606118
November791018
December1,12402

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 13.8 km from Reading. 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 USC00203823 (Hillsdale). Public domain.