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USDA Hardiness Zone 5b

Frost Dates for 16701 — Bradford, Pennsylvania

NOAA 1991–2020 normals from Bradford 4SW Rsch 5, PA (1,660 ft), 4 miles southwest.

Updated

In Bradford, the last spring frost (32°F) is around May 18 in half of years and has passed by May 31 in nine years out of ten. The first fall frost comes around October 4, as early as September 21 one year in ten, leaving a typical freeze-free season of 140 days (NOAA, Bradford 4SW Rsch 5, PA).

Last spring frost
May 18

50% probability

First fall frost
October 4

50% probability

Growing season
140 days

freeze-free, 50%

Hardiness zone
5b

-15 to -10°F (-26.1 to -23.3°C) coldest night

First snow
November 8

median, 1991–2020

Last snow
April 5

median, 1991–2020

Winters with snow
100%

30 of 30 observed

Snow per year
75.2"

NOAA normal

Frost risk by date in Bradford

Half of springs at Bradford 4SW Rsch 5, PA see their last 32°F night by May 18; only one in ten is past it by April 30, and one in ten still has one after May 31. Planting tender crops after May 24 leaves a 30% risk of a frost on them, after May 27 20%, and after May 31 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 94% of the 176 Pennsylvania stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 4 in half of years, as early as September 21 one year in ten, and holds off past October 19 one year in ten. A hard freeze of 28°F follows 13 days later, around October 17; in spring the one-in-ten date for 28°F is May 23, 8 days before the 32°F one. The freeze-free season lasts 140 days in a typical year, shorter than at 94% of the 176 Pennsylvania stations; it reaches 161 days one year in ten and falls short of 122 one year in ten. On average 169 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 11 days longer, to about May 29, and return around September 24. Severe cold of 16°F or below comes every winter, usually between November 21 and March 31.

Spring: the chance of another night this cold after the date
Low90%80%70%60%50%40%30%20%10%
36°FMay 14May 21May 24May 26May 29May 31Jun 3Jun 6Jun 11
32°FApr 30May 6May 11May 15May 18May 21May 24May 27May 31
28°FApr 20Apr 25Apr 28Apr 30May 4May 8May 12May 17May 23
24°FApr 8Apr 13Apr 17Apr 20Apr 23Apr 26Apr 30May 4May 9
20°FMar 29Apr 2Apr 3Apr 6Apr 8Apr 11Apr 15Apr 18Apr 25
16°FMar 16Mar 21Mar 24Mar 28Mar 31Apr 1Apr 3Apr 6Apr 11
Fall: the chance the first night this cold has come by the date
Low10%20%30%40%50%60%70%80%90%
36°FSep 10Sep 16Sep 19Sep 22Sep 24Sep 27Sep 29Oct 2Oct 6
32°FSep 21Sep 26Sep 29Oct 1Oct 4Oct 7Oct 10Oct 14Oct 19
28°FOct 1Oct 7Oct 11Oct 14Oct 17Oct 21Oct 24Oct 28Nov 2
24°FOct 14Oct 21Oct 25Oct 28Oct 31Nov 2Nov 5Nov 8Nov 14
20°FOct 29Nov 1Nov 4Nov 7Nov 10Nov 13Nov 17Nov 21Nov 27
16°FNov 6Nov 10Nov 14Nov 18Nov 21Nov 25Nov 29Dec 2Dec 8

Freeze probabilities 1991–2020 at Bradford 4SW Rsch 5, PA, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.

Frost risk on any date in 16701 →Compare Bradford with another place →

Weather by month in Bradford

July is the warmest month at Bradford 4SW Rsch 5, PA, averaging 79°F by day and 55°F at night; January is the coldest at 31°F and 13°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 89% of years.

Warmth for growing adds up to 2,058 growing degree days a year (base 50°F), fewer than at 95% of the 176 Pennsylvania stations. 33% of them (671) have built up by the end of June, and July adds the most, 530. Precipitation totals 49.6 inches a year, most in July (5.0") and least in February (2.8"); May to September bring 47% of it.

Monthly normals 1991–2020 at Bradford 4SW Rsch 5, PA
MonthHigh °FLow °FPrecip. in32°F nightNights ≤ 32°FGDD 50°F
Jan31133.8100%291
Feb33132.8100%270
Mar42213.3100%277
Apr56324.2100%1850
May68424.589%5209
Jun76514.88%0405
Jul79555.00%0530
Aug78544.60%0487
Sep71474.235%1284
Oct59374.498%1275
Nov46283.9100%2210
Dec35204.1100%281

Monthly normals 1991–2020 at Bradford 4SW Rsch 5, PA (1,660 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.

Compared with the next station

The nearest other station, Bradford Regional Airport, PA, 10 miles south of Bradford and 457 feet higher, has the same 50% last-frost date, a first frost 3 days earlier (October 1), a season 4 days shorter.

Frost dates for 16738 (Lewis Run) →

When it snows in Bradford, Pennsylvania

The first measurable snow (0.1 inch or more) in Bradford usually arrives around November 8, and the last of the season around April 5. Those are the middle dates across the winters of 1991–2020 at Bradford 4SW Rsch 5, PA, 4.4 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 43 days after the last snow.

Planting calendar for 16701

What to do and when, from the 50% frost dates for Bradford, Pennsylvania
WhenWhat to do
March 9 – March 23Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out.
March 23 – April 6Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early.
April 20 – May 4Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil.
May 18 onwardTransplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast.
by July 12Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops.
by September 20Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation.
October 4 onwardPlant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter.

The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.

Where these figures come from

ZIP 16701 is 4 miles from Bradford 4SW Rsch 5, PA, which stands at 1,660 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 16701 in zone 5b, the band where the coldest night of the year averaged -15 to -10°F (-26.1 to -23.3°C) over 1991–2020; a zone describes winter lows, not frost dates.

Frost dates across Pennsylvania →

Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.

Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.

Other zone 5b places in Pennsylvania