Bridgeport climate

Bridgeport Frost Dates and Growing Season

NOAA 1991-2020 normals for Bridgeport, 2 km from Bridgeport, elevation 769 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Bridgeport. 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 March 29 and the first fall freeze around November 7, a growing season of about 222 days.

Median at 36°F
last April 10, first October 30
Median at 32°F
last March 29, first November 7
Median at 28°F
last March 15, first November 16

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 26Apr 21Apr 17Apr 13Apr 10Apr 6Apr 3Mar 30Mar 25
32°FApr 16Apr 9Apr 4Apr 1Mar 29Mar 26Mar 22Mar 17Mar 11
28°FApr 1Mar 27Mar 23Mar 19Mar 15Mar 12Mar 8Mar 3Feb 26
24°FMar 22Mar 15Mar 11Mar 7Mar 4Mar 1Feb 25Feb 19Feb 9
20°FMar 10Mar 4Feb 28Feb 23Feb 16Feb 9Feb 2Jan 28Jan 17
16°FMar 1Feb 19Feb 10Feb 3Jan 29Jan 22Jan 15Jan 5Dec 27

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 24Oct 27Oct 30Nov 1Nov 4Nov 8Nov 13
32°FOct 25Oct 30Nov 2Nov 5Nov 7Nov 10Nov 13Nov 17Nov 23
28°FNov 1Nov 7Nov 10Nov 13Nov 16Nov 20Nov 23Nov 29Dec 4
24°FNov 10Nov 15Nov 20Nov 25Nov 28Dec 2Dec 5Dec 11Dec 18
20°FNov 20Nov 28Dec 3Dec 7Dec 12Dec 18Dec 24Jan 2Jan 11
16°FDec 5Dec 11Dec 18Dec 23Dec 30Jan 4Jan 10Jan 17Feb 3

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°F226217211207202198193187180
32°F245238233227222217213206199
28°F270262255250245240236229220
24°F300290282277272266261254244
20°F337326316308303295288278267
16°F365365354345337331323312301

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
99% of years
16°F or colder
83% 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
2,728
Cooling degree days, base 65°F
2,410
Growing degree days, base 40°F
8,992
Growing degree days, base 45°F
7,383
Growing degree days, base 50°F
5,914
Growing degree days, base 55°F
4,598
Growing degree days, base 60°F
3,426

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January668144
February499480
March33721213
April12976406
May23234676
June0450900
July05841,049
August05731,038
September7341784
October104108476
November34915187
December613260

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 2 km from Bridgeport. 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 USC00411063 (Bridgeport). Public domain.