USDA Hardiness Zone 4a
Frost Dates for 54873 — Solon Springs, Wisconsin
NOAA 1991–2020 normals from Solon Springs, WI (1,130 ft), 6 miles west.
Updated
In Solon Springs, the last spring frost (32°F) is around May 12 in half of years and has passed by May 27 in nine years out of ten. The first fall frost comes around October 2, as early as September 17 one year in ten, leaving a typical freeze-free season of 142 days (NOAA, Solon Springs, WI).
- Last spring frost
- May 12
- First fall frost
- October 2
- Growing season
- 142 days
- Hardiness zone
- 4a
50% probability
50% probability
freeze-free, 50%
-30 to -25°F (-34.4 to -31.7°C) coldest night
- First snow
- November 8
- Last snow
- April 17
- Winters with snow
- 100%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
17 of 17 observed
NOAA normal
Frost risk by date in Solon Springs
Half of springs at Solon Springs, WI see their last 32°F night by May 12; only one in ten is past it by April 28, and one in ten still has one after May 27. Planting tender crops after May 18 leaves a 30% risk of a frost on them, after May 21 20%, and after May 27 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 2 in half of years, as early as September 17 one year in ten, and holds off past October 16 one year in ten. A hard freeze of 28°F follows 11 days later, around October 13; in spring the one-in-ten date for 28°F is May 14, 13 days before the 32°F one. The freeze-free season lasts 142 days in a typical year, shorter than at 81% of the 182 Wisconsin stations; it reaches 160 days one year in ten and falls short of 121 one year in ten. On average 193 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 14 days longer, to about May 26, and return around September 22. Severe cold of 16°F or below comes every winter, usually between November 13 and April 3.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 11 | May 16 | May 19 | May 23 | May 26 | May 29 | May 31 | Jun 3 | Jun 7 |
| 32°F | Apr 28 | May 2 | May 4 | May 7 | May 12 | May 14 | May 18 | May 21 | May 27 |
| 28°F | Apr 16 | Apr 21 | Apr 24 | Apr 28 | Apr 30 | May 2 | May 5 | May 9 | May 14 |
| 24°F | Apr 5 | Apr 9 | Apr 14 | Apr 17 | Apr 20 | Apr 22 | Apr 25 | Apr 28 | May 2 |
| 20°F | Mar 31 | Apr 3 | Apr 5 | Apr 7 | Apr 10 | Apr 13 | Apr 16 | Apr 19 | Apr 24 |
| 16°F | Mar 19 | Mar 25 | Mar 30 | Apr 1 | Apr 3 | Apr 5 | Apr 7 | Apr 11 | Apr 16 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 7 | Sep 13 | Sep 16 | Sep 19 | Sep 22 | Sep 25 | Sep 28 | Oct 1 | Oct 5 |
| 32°F | Sep 17 | Sep 22 | Sep 27 | Sep 30 | Oct 2 | Oct 4 | Oct 8 | Oct 11 | Oct 16 |
| 28°F | Sep 29 | Oct 3 | Oct 8 | Oct 10 | Oct 13 | Oct 16 | Oct 20 | Oct 24 | Oct 30 |
| 24°F | Oct 10 | Oct 16 | Oct 20 | Oct 24 | Oct 28 | Oct 31 | Nov 2 | Nov 5 | Nov 9 |
| 20°F | Oct 23 | Oct 29 | Nov 1 | Nov 3 | Nov 5 | Nov 7 | Nov 10 | Nov 14 | Nov 18 |
| 16°F | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 13 | Nov 16 | Nov 18 | Nov 22 | Nov 26 |
Freeze probabilities 1991–2020 at Solon Springs, 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 54873 →Compare Solon Springs with another place →
Weather by month in Solon Springs
July is the warmest month at Solon Springs, WI, averaging 81°F by day and 58°F at night; January is the coldest at 21°F and 4°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 83% of years.
Warmth for growing adds up to 2,183 growing degree days a year (base 50°F), fewer than at 77% of the 182 Wisconsin stations. 31% of them (684) have built up by the end of June, and July adds the most, 600.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 21 | 4 | 100% | 31 | 0 |
| Feb | 27 | 6 | 100% | 27 | 0 |
| Mar | 39 | 18 | 100% | 29 | 6 |
| Apr | 53 | 31 | 100% | 22 | 33 |
| May | 67 | 43 | 83% | 7 | 206 |
| Jun | 77 | 52 | 4% | <1 | 441 |
| Jul | 81 | 58 | 0% | 0 | 600 |
| Aug | 80 | 56 | 0% | 0 | 550 |
| Sep | 70 | 47 | 42% | 4 | 285 |
| Oct | 56 | 36 | 100% | 17 | 60 |
| Nov | 39 | 24 | 100% | 27 | 3 |
| Dec | 26 | 11 | 100% | 31 | 0 |
Monthly normals 1991–2020 at Solon Springs, WI (1,130 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, Brule Rs, WI, 14 miles northeast of Solon Springs, has a last frost 12 days later (May 24), a first frost 6 days earlier (September 26), a season 18 days shorter.
When it snows in Solon Springs, Wisconsin
The first measurable snow (0.1 inch or more) in Solon Springs usually arrives around November 8, and the last of the season around April 17. Those are the middle dates across the winters of 1991–2020 at Solon Springs, WI, 5.7 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 25 days after the last snow.
Planting calendar for 54873
| When | What to do |
|---|---|
| March 3 – March 17 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 17 – March 31 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 14 – April 28 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 12 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 10 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 18 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 2 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 54873 is 6 miles from Solon Springs, WI, which stands at 1,130 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 54873 in zone 4a, the band where the coldest night of the year averaged -30 to -25°F (-34.4 to -31.7°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.