Frost dates for 53805Boscobel, WI
The average last spring frost in Boscobel is May 3 and the average first fall frost is October 7, giving a typical growing season of about 155 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 3
- Average first fall frost
- Oct 7
- Growing season
- 155 days
Safer after May 18 (1-in-10 risk)
Possible by Sep 25 (1-in-10 risk)
Last frost typically in 181 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 14 · May 28 | Sep 17 · Sep 29 · Oct 11 | 136 days | 100% |
| Frost / freeze (32°F) | Apr 19 · May 3 · May 18 | Sep 25 · Oct 7 · Oct 20 | 155 days | 100% |
| Hard freeze (28°F) | Apr 7 · Apr 22 · May 8 | Oct 4 · Oct 17 · Oct 31 | 177 days | 100% |
Planting calendar for Boscobel
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 2 – Jun 8 |
| Tomatoes | Transplant outdoors | May 19 – Jun 17 |
| Peppers | Start seeds indoors | Apr 2 – May 3 |
| Peppers | Transplant outdoors | Jun 2 – Jul 3 |
| Eggplant | Start seeds indoors | Apr 19 – May 18 |
| Eggplant | Transplant outdoors | Jun 2 – Jul 3 |
| Cucumbers | Sow outdoors | Jun 2 – Jun 27 |
| Summer squash | Sow outdoors | May 19 – Jul 3 |
| Winter squash & pumpkins | Sow outdoors | Jun 2 – Jul 3 |
| Snap beans | Sow outdoors | May 19 – Jul 20 |
| Sweet corn | Sow outdoors | May 19 – Jun 17 |
| Watermelon & cantaloupe | Sow outdoors | Jun 2 – Jul 3 |
| Okra | Sow outdoors | May 26 – Jun 18 |
| Peas | Sow outdoors (spring) | Apr 2 – May 18 |
| Potatoes | Plant outdoors (spring) | Apr 2 – Jun 2 |
| Onions | Start seeds indoors (spring) | Feb 19 – Mar 18 |
| Onions | Transplant outdoors (spring) | Apr 19 – May 18 |
| Broccoli | Start seeds indoors (spring) | Mar 15 – Apr 18 |
| Broccoli | Transplant outdoors (spring) | Apr 19 – May 18 |
| Broccoli | Start seeds indoors (fall) | Jun 7 – Jun 17 |
| Broccoli | Transplant outdoors (fall) | Jul 7 – Jul 18 |
| Cabbage | Start seeds indoors (spring) | Mar 5 – Apr 2 |
| Cabbage | Transplant outdoors (spring) | Apr 2 – May 3 |
| Cabbage | Start seeds indoors (fall) | May 28 – Jun 27 |
| Cabbage | Transplant outdoors (fall) | Jun 27 – Jul 28 |
| Leaf lettuce | Sow outdoors (spring) | Apr 2 – Jun 18 |
| Leaf lettuce | Sow outdoors (fall) | Jun 27 – Aug 13 |
| Spinach | Sow outdoors (spring) | Mar 26 – May 9 |
| Spinach | Sow outdoors (fall) | Jul 14 – Aug 18 |
| Radishes | Sow outdoors (spring) | Apr 2 – May 23 |
| Radishes | Sow outdoors (fall) | Jun 27 – Aug 28 |
| Kale | Sow outdoors (spring) | Apr 19 – May 9 |
| Kale | Sow outdoors (fall) | Jun 20 – Jul 28 |
| Carrots | Sow outdoors (spring) | May 3 – Jun 18 |
| Carrots | Sow outdoors (fall) | May 28 – Jul 13 |
| Garlic | Plant outdoors (fall) | Sep 27 – Oct 28 |
Where these dates come from
ZIP code 53805 is matched to the NOAA station Boscobel Ap, WI, 3 km away, at 672 ft elevation (3 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Boscobel Ap, WI (used) | 672 ft | May 3 | Oct 7 |
| Steuben 4 Se, WI | 1,015 ft | Apr 22 | Oct 20 |
| Gays Mills, WI | 689 ft | May 3 | Oct 7 |
| Lynxville Dam 9, WI | 633 ft | Apr 24 | Oct 17 |
Frost dates near Boscobel
- Woodman, WI 53827 · last May 3, first Oct 7
- Steuben, WI 54657 · last Apr 22, first Oct 20
- Blue River, WI 53518 · last May 3, first Oct 7
- Fennimore, WI 53809 · last Apr 27, first Oct 11
- Wauzeka, WI 53826 · last Apr 22, first Oct 20
- Muscoda, WI 53573 · last May 5, first Oct 6
- Gays Mills, WI 54631 · last May 3, first Oct 7
- Mount Hope, WI 53816 · last Apr 27, first Oct 11
Frequently asked questions
- When is the last frost in Boscobel, WI?
- For ZIP code 53805, the average last spring frost (32°F) is May 3, based on NOAA 1991-2020 climate normals for the Boscobel Ap, WI weather station. There is a 1-in-10 chance of a frost after May 18.
- When is the first frost in Boscobel, WI?
- The average first fall frost (32°F) is October 7. There is a 1-in-10 chance of frost by September 25, so tender plants are at risk from that point on.
- How long is the growing season in 53805?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 155 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.