Newcastle climate

Newcastle Frost Dates and Growing Season

NOAA 1991-2020 normals for Graham, 18 km from Newcastle, elevation 1078 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Graham. 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 1 and the first fall freeze around November 5, a growing season of about 220 days.

Median at 36°F
last April 13, first October 29
Median at 32°F
last April 1, first November 5
Median at 28°F
last March 15, first November 14

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°FApr 28Apr 24Apr 20Apr 17Apr 13Apr 8Apr 5Apr 1Mar 25
32°FApr 20Apr 13Apr 7Apr 3Apr 1Mar 27Mar 22Mar 16Mar 10
28°FApr 8Apr 1Mar 26Mar 20Mar 15Mar 11Mar 7Mar 2Feb 25
24°FMar 23Mar 14Mar 9Mar 5Mar 1Feb 27Feb 23Feb 17Feb 9
20°FMar 7Mar 2Feb 26Feb 21Feb 15Feb 10Feb 4Jan 28Jan 15
16°FFeb 27Feb 16Feb 10Feb 4Jan 30Jan 24Jan 17Jan 4Dec 23

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 15Oct 20Oct 23Oct 26Oct 29Nov 1Nov 3Nov 6Nov 10
32°FOct 23Oct 28Nov 1Nov 2Nov 5Nov 8Nov 11Nov 14Nov 20
28°FOct 31Nov 3Nov 7Nov 11Nov 14Nov 18Nov 22Nov 27Dec 2
24°FNov 6Nov 12Nov 17Nov 21Nov 26Nov 29Dec 3Dec 10Dec 18
20°FNov 16Nov 25Nov 30Dec 4Dec 11Dec 18Dec 24Jan 1Jan 12
16°FNov 29Dec 7Dec 15Dec 22Dec 28Jan 3Jan 9Jan 20Feb 2

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°F220213208203198193188184177
32°F246238232225220215210203194
28°F270261254250244239233227216
24°F300289282276270264258251240
20°F336327317310304296288281270
16°F365364352344336330323313302

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
98% of years
16°F or colder
78% 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
2,723
Cooling degree days, base 65°F
2,584
Growing degree days, base 40°F
9,179
Growing degree days, base 45°F
7,566
Growing degree days, base 50°F
6,093
Growing degree days, base 55°F
4,769
Growing degree days, base 60°F
3,598

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January669142
February500378
March31525233
April13287416
May25253693
June0482931
July06281,093
August06111,075
September9361802
October107118484
November35813182
December608263

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 18 km from Newcastle. 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 USC00413668 (Graham). Public domain.