Palmyra climate

Palmyra Frost Dates and Growing Season

NOAA 1991-2020 normals for Syracuse, 17.2 km from Palmyra, elevation 1100 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Syracuse. 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 25 and the first fall freeze around October 11, a growing season of about 168 days.

Median at 36°F
last May 3, first October 1
Median at 32°F
last April 25, first October 11
Median at 28°F
last April 16, first October 22

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 16May 11May 7May 5May 3Apr 30Apr 29Apr 25Apr 20
32°FMay 7May 3Apr 30Apr 27Apr 25Apr 22Apr 19Apr 16Apr 12
28°FApr 29Apr 25Apr 22Apr 19Apr 16Apr 14Apr 10Apr 7Apr 2
24°FApr 21Apr 17Apr 13Apr 10Apr 7Apr 3Mar 31Mar 28Mar 21
20°FApr 11Apr 6Apr 2Mar 31Mar 28Mar 24Mar 20Mar 15Mar 8
16°FApr 4Mar 30Mar 25Mar 20Mar 16Mar 13Mar 9Mar 6Mar 2

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 7Oct 10Oct 14
32°FSep 25Oct 1Oct 5Oct 8Oct 11Oct 14Oct 17Oct 20Oct 24
28°FOct 6Oct 11Oct 16Oct 19Oct 22Oct 24Oct 26Oct 30Nov 2
24°FOct 17Oct 22Oct 25Oct 29Oct 31Nov 2Nov 4Nov 7Nov 12
20°FOct 25Oct 31Nov 3Nov 5Nov 8Nov 11Nov 14Nov 18Nov 24
16°FNov 1Nov 6Nov 10Nov 14Nov 17Nov 20Nov 23Nov 28Dec 4

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°F168162158154150147143138132
32°F187180175171168165161155149
28°F207200195191187183180175168
24°F226219214209206202198193186
20°F245239233228223219214209202
16°F266259253246242237231225217

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
6,116
Cooling degree days, base 65°F
1,121
Growing degree days, base 40°F
5,722
Growing degree days, base 45°F
4,553
Growing degree days, base 50°F
3,511
Growing degree days, base 55°F
2,589
Growing degree days, base 60°F
1,794

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,28600
February1,03204
March786239
April43910135
May16774382
June16238672
July2356818
August5298758
September91127489
October37718186
November773027
December1,14201

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 17.2 km from Palmyra. 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 USC00258395 (Syracuse). Public domain.