USDA Hardiness Zone 5b
Frost Dates for 53115 — Delavan, Wisconsin
NOAA 1991–2020 normals from Delavan Wwtp, WI (882 ft), 1 miles west.
Updated
In Delavan, the last spring frost (32°F) is around April 28 in half of years and has passed by May 14 in nine years out of ten. The first fall frost comes around October 14, as early as September 28 one year in ten, leaving a typical freeze-free season of 168 days (NOAA, Delavan Wwtp, WI).
- Last spring frost
- April 28
- First fall frost
- October 14
- Growing season
- 168 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 9
- Last snow
- April 12
- Winters with snow
- 100%
- Snow per year
- 40.1"
median, 1991–2020
median, 1991–2020
16 of 16 observed
NOAA normal
Frost risk by date in Delavan
Half of springs at Delavan Wwtp, WI see their last 32°F night by April 28; only one in ten is past it by April 12, and one in ten still has one after May 14. Planting tender crops after May 4 leaves a 30% risk of a frost on them, after May 8 20%, and after May 14 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 14 in half of years, as early as September 28 one year in ten, and holds off past October 26 one year in ten. A hard freeze of 28°F follows 11 days later, around October 25; in spring the one-in-ten date for 28°F is May 1, 13 days before the 32°F one. The freeze-free season lasts 168 days in a typical year, longer than at 82% of the 182 Wisconsin stations; it reaches 188 days one year in ten and falls short of 146 one year in ten. On average 143 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 10, and return around October 3. Severe cold of 16°F or below comes every winter, usually between November 29 and March 13.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 26 | Apr 30 | May 3 | May 7 | May 10 | May 13 | May 17 | May 21 | May 26 |
| 32°F | Apr 12 | Apr 17 | Apr 20 | Apr 24 | Apr 28 | Apr 30 | May 4 | May 8 | May 14 |
| 28°F | Apr 2 | Apr 6 | Apr 9 | Apr 12 | Apr 15 | Apr 18 | Apr 22 | Apr 26 | May 1 |
| 24°F | Mar 17 | Mar 24 | Mar 29 | Mar 31 | Apr 3 | Apr 5 | Apr 8 | Apr 13 | Apr 18 |
| 20°F | Mar 8 | Mar 13 | Mar 17 | Mar 20 | Mar 24 | Mar 27 | Mar 31 | Apr 2 | Apr 6 |
| 16°F | Feb 28 | Mar 4 | Mar 8 | Mar 11 | Mar 13 | Mar 17 | Mar 20 | Mar 24 | Mar 29 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 20 | Sep 24 | Sep 28 | Oct 1 | Oct 3 | Oct 6 | Oct 8 | Oct 12 | Oct 15 |
| 32°F | Sep 28 | Oct 3 | Oct 7 | Oct 11 | Oct 14 | Oct 16 | Oct 19 | Oct 22 | Oct 26 |
| 28°F | Oct 8 | Oct 15 | Oct 19 | Oct 23 | Oct 25 | Oct 28 | Oct 31 | Nov 3 | Nov 8 |
| 24°F | Oct 25 | Oct 30 | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 14 | Nov 17 | Nov 22 |
| 20°F | Nov 4 | Nov 9 | Nov 12 | Nov 15 | Nov 18 | Nov 21 | Nov 25 | Nov 29 | Dec 3 |
| 16°F | Nov 13 | Nov 17 | Nov 22 | Nov 26 | Nov 29 | Dec 2 | Dec 5 | Dec 9 | Dec 17 |
Freeze probabilities 1991–2020 at Delavan Wwtp, 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 53115 →Compare Delavan with another place →
Compared with the next station
The nearest other station, Lake Geneva Wwtp, WI, 11 miles east of Delavan, has a last frost 3 days earlier (April 25), a first frost 7 days later (October 21), a season 11 days longer.
When it snows in Delavan, Wisconsin
The first measurable snow (0.1 inch or more) in Delavan usually arrives around November 9, and the last of the season around April 12. Those are the middle dates across the winters of 1991–2020 at Lake Geneva Wwtp, WI, 11.1 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 16 days after the last snow.
Planting calendar for 53115
| When | What to do |
|---|---|
| February 17 – March 3 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 3 – March 17 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 31 – April 14 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 28 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 22 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 30 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 14 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 53115 is 1 mile from Delavan Wwtp, WI, which stands at 882 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 53121 (Elkhorn). The 2023 USDA Plant Hardiness Zone Map lists ZIP 53115 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.