Passaic County climate

Passaic County Frost Dates and Growing Season

NOAA 1991-2020 normals for Wanaque Raymond Dam, 1.3 km from Passaic County, elevation 245 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Wanaque Raymond Dam. 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 19 and the first fall freeze around October 23, a growing season of about 188 days.

Median at 36°F
last April 30, first October 13
Median at 32°F
last April 19, first October 23
Median at 28°F
last April 4, first November 4

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 10May 6May 3Apr 30Apr 28Apr 25Apr 22Apr 18
32°FMay 3Apr 28Apr 25Apr 22Apr 19Apr 16Apr 12Apr 9Apr 5
28°FApr 19Apr 14Apr 9Apr 6Apr 4Apr 2Mar 31Mar 27Mar 21
24°FApr 7Apr 3Mar 31Mar 29Mar 25Mar 22Mar 19Mar 15Mar 10
20°FMar 29Mar 24Mar 20Mar 17Mar 14Mar 12Mar 9Mar 6Mar 1
16°FMar 21Mar 15Mar 13Mar 10Mar 7Mar 4Mar 2Feb 26Feb 18

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 3Oct 5Oct 8Oct 10Oct 13Oct 16Oct 18Oct 22Oct 27
32°FOct 9Oct 13Oct 16Oct 20Oct 23Oct 26Oct 29Nov 2Nov 6
28°FOct 16Oct 24Oct 29Nov 1Nov 4Nov 8Nov 11Nov 16Nov 21
24°FOct 28Nov 5Nov 10Nov 15Nov 18Nov 22Nov 27Dec 1Dec 6
20°FNov 12Nov 21Nov 26Nov 30Dec 3Dec 6Dec 11Dec 16Dec 23
16°FDec 1Dec 6Dec 10Dec 15Dec 19Dec 23Dec 27Jan 1Jan 7

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°F182177171168164161157153147
32°F207200196191188184179174167
28°F235228222218213209205200193
24°F264255249244239234229223215
20°F288280274269264259254248239
16°F310302296292287283278271264

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
5,635
Cooling degree days, base 65°F
837
Growing degree days, base 40°F
5,376
Growing degree days, base 45°F
4,180
Growing degree days, base 50°F
3,137
Growing degree days, base 55°F
2,230
Growing degree days, base 60°F
1,462

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,12201
February97300
March825013
April479792
May18841324
June34150565
July1288752
August4247708
September7098479
October3607169
November642030
December93804

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 1.3 km from Passaic County. 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 USC00289187 (Wanaque Raymond Dam). Public domain.