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USDA Hardiness Zone 5a

Frost Dates for 53017 — Colgate, Wisconsin

NOAA 1991–2020 normals from Richfield 3 SSW, WI (984 ft), 3 miles east.

Updated

In Colgate, the last spring frost (32°F) is around April 30 in half of years and has passed by May 16 in nine years out of ten. The first fall frost comes around October 16, as early as October 1 one year in ten, leaving a typical freeze-free season of 167 days (NOAA, Richfield 3 SSW, WI).

Last spring frost
April 30

50% probability

First fall frost
October 16

50% probability

Growing season
167 days

freeze-free, 50%

Hardiness zone
5a

-20 to -15°F (-28.9 to -26.1°C) coldest night

First snow
November 17

median, 1991–2020

Last snow
April 9

median, 1991–2020

Winters with snow
100%

29 of 29 observed

Snow per year
54.3"

NOAA normal

Frost risk by date in Colgate

Half of springs at Richfield 3 SSW, WI see their last 32°F night by April 30; only one in ten is past it by April 16, and one in ten still has one after May 16. Planting tender crops after May 6 leaves a 30% risk of a frost on them, after May 11 20%, and after May 16 10%. The 16 days between the even-odds date and the one-in-ten date is wider than at 70% of the 182 Wisconsin stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 16 in half of years, as early as October 1 one year in ten, and holds off past October 29 one year in ten. A hard freeze of 28°F follows 11 days later, around October 27; in spring the one-in-ten date for 28°F is May 4, 12 days before the 32°F one. The freeze-free season lasts 167 days in a typical year, longer than at 79% of the 182 Wisconsin stations; it reaches 187 days one year in ten and falls short of 147 one year in ten. On average 153 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 12 days longer, to about May 12, and return around October 4. Severe cold of 16°F or below comes every winter, usually between November 24 and March 18.

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

Freeze probabilities 1991–2020 at Richfield 3 SSW, WI, 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 53017 →Compare Colgate with another place →

Compared with the next station

The nearest other station, Germantown, WI, 8 miles east of Colgate, has a last frost 6 days later (May 6), a first frost 8 days earlier (October 8), a season 13 days shorter.

Frost dates for 53051 (Menomonee Falls) →

When it snows in Colgate, Wisconsin

The first measurable snow (0.1 inch or more) in Colgate usually arrives around November 17, and the last of the season around April 9. Those are the middle dates across the winters of 1991–2020 at Germantown, WI, 7.5 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 21 days after the last snow.

Planting calendar for 53017

What to do and when, from the 50% frost dates for Colgate, Wisconsin
WhenWhat to do
February 19 – March 5Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out.
March 5 – March 19Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early.
April 2 – April 16Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil.
April 30 onwardTransplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast.
by July 24Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops.
by October 2Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation.
October 16 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 53017 is 3 miles from Richfield 3 SSW, WI, which stands at 984 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 53089 (Sussex). The 2023 USDA Plant Hardiness Zone Map lists ZIP 53017 in zone 5a, the band where the coldest night of the year averaged -20 to -15°F (-28.9 to -26.1°C) over 1991–2020; a zone describes winter lows, not frost dates.

Frost dates across Wisconsin →

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.

ZIP codes measured at the same station

Other zone 5a places in Wisconsin