USDA Hardiness Zone 5b
Frost Dates for 53527 — Cottage Grove, Wisconsin
NOAA 1991–2020 normals from Madison Dane Regional Airport, WI (866 ft), 9 miles northwest.
Updated
In Cottage Grove, the last spring frost (32°F) is around May 1 in half of years and has passed by May 16 in nine years out of ten. The first fall frost comes around October 10, as early as September 26 one year in ten, leaving a typical freeze-free season of 160 days (NOAA, Madison Dane Regional Airport, WI).
- Last spring frost
- May 1
- First fall frost
- October 10
- Growing season
- 160 days
- Hardiness zone
- 5b
50% probability
50% probability
freeze-free, 50%
-15 to -10°F (-26.1 to -23.3°C) coldest night
- First snow
- November 10
- Last snow
- April 13
- Winters with snow
- 100%
- Snow per year
- 51.8"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Cottage Grove
Half of springs at Madison Dane Regional Airport, WI see their last 32°F night by May 1; 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 7 leaves a 30% risk of a frost on them, after May 11 20%, and after May 16 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 30% of the 182 Wisconsin stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 10 in half of years, as early as September 26 one year in ten, and holds off past October 24 one year in ten. A hard freeze of 28°F follows 12 days later, around October 22; in spring the one-in-ten date for 28°F is May 5, 11 days before the 32°F one. The freeze-free season lasts 160 days in a typical year, longer than at 60% of the 182 Wisconsin stations; it reaches 179 days one year in ten and falls short of 140 one year in ten. On average 147 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 13, and return around September 29. Severe cold of 16°F or below comes every winter, usually between November 22 and March 19.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 29 | May 2 | May 6 | May 10 | May 13 | May 16 | May 19 | May 23 | May 29 |
| 32°F | Apr 16 | Apr 22 | Apr 25 | Apr 29 | May 1 | May 3 | May 7 | May 11 | May 16 |
| 28°F | Apr 5 | Apr 10 | Apr 13 | Apr 17 | Apr 20 | Apr 23 | Apr 26 | Apr 30 | May 5 |
| 24°F | Mar 25 | Mar 31 | Apr 2 | Apr 4 | Apr 7 | Apr 10 | Apr 13 | Apr 17 | Apr 22 |
| 20°F | Mar 14 | Mar 19 | Mar 22 | Mar 26 | Mar 30 | Apr 1 | Apr 3 | Apr 6 | Apr 12 |
| 16°F | Mar 6 | Mar 11 | Mar 14 | Mar 17 | Mar 19 | Mar 22 | Mar 25 | Mar 30 | Apr 2 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 17 | Sep 21 | Sep 24 | Sep 27 | Sep 29 | Oct 2 | Oct 4 | Oct 7 | Oct 12 |
| 32°F | Sep 26 | Sep 30 | Oct 4 | Oct 7 | Oct 10 | Oct 12 | Oct 15 | Oct 18 | Oct 24 |
| 28°F | Oct 6 | Oct 12 | Oct 16 | Oct 19 | Oct 22 | Oct 25 | Oct 28 | Oct 31 | Nov 4 |
| 24°F | Oct 19 | Oct 25 | Oct 29 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 12 | Nov 17 |
| 20°F | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 13 | Nov 15 | Nov 18 | Nov 22 | Nov 26 |
| 16°F | Nov 6 | Nov 12 | Nov 15 | Nov 19 | Nov 22 | Nov 25 | Nov 28 | Dec 1 | Dec 7 |
Freeze probabilities 1991–2020 at Madison Dane Regional Airport, 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 53527 →Compare Cottage Grove with another place →
Weather by month in Cottage Grove
July is the warmest month at Madison Dane Regional Airport, WI, averaging 82°F by day and 62°F at night; January is the coldest at 27°F and 12°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 52% of years.
Warmth for growing adds up to 2,669 growing degree days a year (base 50°F), more than at 79% of the 182 Wisconsin stations. 33% of them (892) have built up by the end of June, and July adds the most, 677. Precipitation totals 37.2 inches a year, most in June (5.3") and least in January (1.5"); May to September bring 58% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 27 | 12 | 1.5 | 100% | 30 | 0 |
| Feb | 31 | 15 | 1.5 | 100% | 27 | 0 |
| Mar | 44 | 25 | 2.3 | 100% | 23 | 15 |
| Apr | 57 | 36 | 3.8 | 100% | 10 | 65 |
| May | 69 | 47 | 4.1 | 52% | 2 | 272 |
| Jun | 79 | 57 | 5.3 | 0% | 0 | 540 |
| Jul | 82 | 62 | 4.5 | 0% | 0 | 677 |
| Aug | 80 | 60 | 4.2 | 0% | 0 | 611 |
| Sep | 73 | 51 | 3.4 | 21% | 1 | 366 |
| Oct | 60 | 40 | 2.8 | 97% | 7 | 109 |
| Nov | 45 | 29 | 2.2 | 100% | 20 | 13 |
| Dec | 32 | 18 | 1.6 | 100% | 28 | 1 |
Monthly normals 1991–2020 at Madison Dane Regional Airport, WI (866 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, Stoughton, WI, 11 miles south of Cottage Grove, has a last frost 1 day earlier (April 30), a first frost 1 day later (October 11), a season 3 days longer.
When it snows in Cottage Grove, Wisconsin
The first measurable snow (0.1 inch or more) in Cottage Grove usually arrives around November 10, and the last of the season around April 13. Those are the middle dates across the winters of 1991–2020 at Madison Dane Regional Airport, WI, 8.8 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 18 days after the last snow.
Planting calendar for 53527
| When | What to do |
|---|---|
| February 20 – March 6 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 6 – March 20 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 3 – April 17 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 1 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 18 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 26 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 10 onward | Plant 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 53527 is 9 miles from Madison Dane Regional Airport, WI, which stands at 866 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 7 other ZIP codes share the station; its figures are presented in full for 53704 (Madison). The 2023 USDA Plant Hardiness Zone Map lists ZIP 53527 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 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.