Frost dates for 53578Prairie Du Sac, WI
The average last spring frost in Prairie Du Sac is May 7 and the average first fall frost is October 1, giving a typical growing season of about 148 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 7
- Average first fall frost
- Oct 1
- Growing season
- 148 days
Safer after May 22 (1-in-10 risk)
Possible by Sep 18 (1-in-10 risk)
Last frost typically in 187 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Apr 30 · May 18 · Jun 1 | Sep 11 · Sep 23 · Oct 6 | 128 days | 100% |
| Frost / freeze (32°F) | Apr 22 · May 7 · May 22 | Sep 18 · Oct 1 · Oct 16 | 148 days | 100% |
| Hard freeze (28°F) | Apr 12 · Apr 27 · May 13 | Sep 26 · Oct 12 · Oct 29 | 167 days | 100% |
Planting calendar for Prairie Du Sac
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Apr 6 – Jun 12 |
| Tomatoes | Transplant outdoors | May 23 – Jun 11 |
| Peppers | Start seeds indoors | Apr 6 – May 7 |
| Peppers | Transplant outdoors | Jun 6 – Jul 7 |
| Eggplant | Start seeds indoors | Apr 23 – May 22 |
| Eggplant | Transplant outdoors | Jun 6 – Jul 7 |
| Cucumbers | Sow outdoors | Jun 6 – Jun 21 |
| Summer squash | Sow outdoors | May 23 – Jul 7 |
| Winter squash & pumpkins | Sow outdoors | Jun 6 – Jul 7 |
| Snap beans | Sow outdoors | May 23 – Jul 14 |
| Sweet corn | Sow outdoors | May 23 – Jun 11 |
| Watermelon & cantaloupe | Sow outdoors | Jun 6 – Jul 7 |
| Okra | Sow outdoors | May 30 – Jun 22 |
| Peas | Sow outdoors (spring) | Apr 6 – May 22 |
| Potatoes | Plant outdoors (spring) | Apr 6 – Jun 6 |
| Onions | Start seeds indoors (spring) | Feb 23 – Mar 22 |
| Onions | Transplant outdoors (spring) | Apr 23 – May 22 |
| Broccoli | Start seeds indoors (spring) | Mar 19 – Apr 22 |
| Broccoli | Transplant outdoors (spring) | Apr 23 – May 22 |
| Broccoli | Start seeds indoors (fall) | Jun 1 – Jun 11 |
| Broccoli | Transplant outdoors (fall) | Jul 1 – Jul 12 |
| Cabbage | Start seeds indoors (spring) | Mar 9 – Apr 6 |
| Cabbage | Transplant outdoors (spring) | Apr 6 – May 7 |
| Cabbage | Start seeds indoors (fall) | May 22 – Jun 21 |
| Cabbage | Transplant outdoors (fall) | Jun 21 – Jul 22 |
| Leaf lettuce | Sow outdoors (spring) | Apr 6 – Jun 22 |
| Leaf lettuce | Sow outdoors (fall) | Jun 21 – Aug 7 |
| Spinach | Sow outdoors (spring) | Mar 30 – May 13 |
| Spinach | Sow outdoors (fall) | Jul 8 – Aug 12 |
| Radishes | Sow outdoors (spring) | Apr 6 – May 27 |
| Radishes | Sow outdoors (fall) | Jun 21 – Aug 22 |
| Kale | Sow outdoors (spring) | Apr 23 – May 13 |
| Kale | Sow outdoors (fall) | Jun 14 – Jul 22 |
| Carrots | Sow outdoors (spring) | May 7 – Jun 22 |
| Carrots | Sow outdoors (fall) | May 22 – Jul 7 |
| Garlic | Plant outdoors (fall) | Sep 21 – Oct 22 |
Where these dates come from
ZIP code 53578 is matched to the NOAA station Mazomanie Wwtp, WI, 15.2 km away, at 764 ft elevation (50 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Mazomanie Wwtp, WI (used) | 764 ft | May 7 | Oct 1 |
| Sauk City Wwtp, WI | 750 ft | May 4 | Oct 6 |
| Lodi, WI | 824 ft | May 1 | Oct 10 |
| Baraboo, WI | 823 ft | May 5 | Oct 5 |
Frost dates near Prairie Du Sac
- Sauk City, WI 53583 · last May 7, first Oct 1
- Mazomanie, WI 53560 · last May 7, first Oct 1
- Merrimac, WI 53561 · last May 1, first Oct 10
- North Freedom, WI 53951 · last Apr 24, first Oct 20
- Lodi, WI 53555 · last May 1, first Oct 10
- Black Earth, WI 53515 · last May 7, first Oct 1
- Dane, WI 53529 · last May 4, first Oct 6
- Reedsburg, WI 53958 · last May 2, first Oct 7
Frequently asked questions
- When is the last frost in Prairie Du Sac, WI?
- For ZIP code 53578, the average last spring frost (32°F) is May 7, based on NOAA 1991-2020 climate normals for the Mazomanie Wwtp, WI weather station. There is a 1-in-10 chance of a frost after May 22.
- When is the first frost in Prairie Du Sac, WI?
- The average first fall frost (32°F) is October 1. There is a 1-in-10 chance of frost by September 18, so tender plants are at risk from that point on.
- How long is the growing season in 53578?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 148 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.