Newark Frost Dates and Growing Season

NOAA 1991-2020 normals for Newark, 1.8 km from Newark, elevation 10 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Newark. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

A freeze (32°F or colder) happens in only 43 percent of years at Newark, so there is no typical freeze season.

Median at 36°F: last January 19, first December 15
Median at 32°F: last January 1, first December 27

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.

Threshold	10%	20%	30%	40%	50%	60%	70%	80%	90%
36°F	Feb 28	Feb 10	Feb 1	Jan 26	Jan 19	Jan 13	Jan 7	Jan 1	Dec 24
32°F	Jan 22	Jan 14	Jan 8	Jan 5	Jan 1	Dec 29	Dec 25	Dec 21	Dec 16
28°F	–	–	–	–	–	–	–	–	–
24°F	–	–	–	–	–	–	–	–	–
20°F	–	–	–	–	–	–	–	–	–
16°F	–	–	–	–	–	–	–	–	–

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.

Threshold	10%	20%	30%	40%	50%	60%	70%	80%	90%
36°F	Nov 27	Dec 4	Dec 8	Dec 12	Dec 15	Dec 19	Dec 24	Jan 1	Jan 9
32°F	Dec 9	Dec 15	Dec 19	Dec 23	Dec 27	Dec 29	Jan 2	Jan 7	Jan 14
28°F	–	–	–	–	–	–	–	–	–
24°F	–	–	–	–	–	–	–	–	–
20°F	–	–	–	–	–	–	–	–	–
16°F	–	–	–	–	–	–	–	–	–

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.

Threshold	10%	20%	30%	40%	50%	60%	70%	80%	90%
36°F	359	349	342	336	329	321	313	302	284
32°F	365	365	365	365	365	364	358	352	343
28°F	365	365	365	365	365	365	365	365	365
24°F	365	365	365	365	365	365	365	365	365
20°F	365	365	365	365	365	365	365	365	365
16°F	365	365	365	365	365	365	365	365	365

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder: 92% of years
32°F or colder: 43% of years
28°F or colder: 2% of years
24°F or colder: 0% of years
20°F or colder: 0% of years
16°F or colder: 0% 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: 2,288
Cooling degree days, base 65°F: 430
Growing degree days, base 40°F: 7,268
Growing degree days, base 45°F: 5,458
Growing degree days, base 50°F: 3,744
Growing degree days, base 55°F: 2,281
Growing degree days, base 60°F: 1,159

Growing degree days by month, base 50°F

Heating and cooling by month

Month	Heating DD	Cooling DD	Growing DD 50
January	451	0	62
February	326	0	111
March	278	2	196
April	205	9	254
May	123	30	372
June	48	65	467
July	16	88	536
August	12	97	550
September	21	95	524
October	86	43	422
November	270	2	188
December	450	0	63

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 1.8 km from Newark. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00046144 (Newark). Public domain.