Port Jervis climate

Port Jervis Frost Dates and Growing Season

NOAA 1991-2020 normals for Port Jervis, 1.6 km from Port Jervis, elevation 580 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Port Jervis. 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 5 and the first fall freeze around October 10, a growing season of about 158 days.

Median at 36°F
last May 16, first October 2
Median at 32°F
last May 5, first October 10
Median at 28°F
last April 23, first October 24

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 25May 22May 19May 16May 13May 9May 6May 1
32°FMay 19May 14May 11May 8May 5May 2Apr 30Apr 26Apr 22
28°FMay 8May 4Apr 30Apr 26Apr 23Apr 20Apr 17Apr 13Apr 8
24°FApr 23Apr 18Apr 15Apr 12Apr 9Apr 6Apr 3Apr 1Mar 28
20°FApr 9Apr 5Apr 2Mar 31Mar 30Mar 28Mar 23Mar 18Mar 13
16°FMar 31Mar 29Mar 25Mar 22Mar 18Mar 15Mar 12Mar 9Mar 3

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 19Sep 24Sep 27Sep 30Oct 2Oct 4Oct 6Oct 9Oct 14
32°FSep 28Oct 1Oct 4Oct 7Oct 10Oct 14Oct 18Oct 22Oct 29
28°FOct 6Oct 11Oct 16Oct 20Oct 24Oct 28Nov 1Nov 3Nov 7
24°FOct 21Oct 28Oct 31Nov 2Nov 5Nov 7Nov 11Nov 15Nov 21
20°FNov 2Nov 7Nov 11Nov 14Nov 18Nov 21Nov 25Nov 29Dec 4
16°FNov 14Nov 18Nov 21Nov 25Nov 28Dec 1Dec 5Dec 9Dec 16

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°F156150145141138135131126120
32°F178171167162158154150146139
28°F203197191187183179174168162
24°F230223217213209205201195187
20°F255248243238233228225220212
16°F279270265260256252247241233

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
6,469
Cooling degree days, base 65°F
582
Growing degree days, base 40°F
4,744
Growing degree days, base 45°F
3,637
Growing degree days, base 50°F
2,664
Growing degree days, base 55°F
1,825
Growing degree days, base 60°F
1,126

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,24101
February1,06001
March91909
April532474
May23330278
June53110507
July6216676
August16166615
September13153375
October4463111
November758016
December1,07402

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 1.6 km from Port Jervis. 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 USC00306774 (Port Jervis). Public domain.