Frost dates for 53570Monticello, WI
The average last spring frost in Monticello is April 27 and the average first fall frost is October 14, giving a typical growing season of about 170 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 27
- Average first fall frost
- Oct 14
- Growing season
- 170 days
Safer after May 12 (1-in-10 risk)
Possible by Sep 29 (1-in-10 risk)
Last frost typically in 178 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 23 · May 6 · May 22 | Sep 21 · Oct 4 · Oct 17 | 149 days | 100% |
| Frost / freeze (32°F) | Apr 12 · Apr 27 · May 12 | Sep 29 · Oct 14 · Oct 29 | 170 days | 100% |
| Hard freeze (28°F) | Apr 2 · Apr 15 · May 1 | Oct 9 · Oct 25 · Nov 7 | 190 days | 100% |
Planting calendar for Monticello
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 | Mar 27 – Jun 2 |
| Tomatoes | Transplant outdoors | May 13 – Jun 24 |
| Peppers | Start seeds indoors | Mar 27 – Apr 27 |
| Peppers | Transplant outdoors | May 27 – Jun 27 |
| Eggplant | Start seeds indoors | Apr 13 – May 12 |
| Eggplant | Transplant outdoors | May 27 – Jun 27 |
| Cucumbers | Sow outdoors | May 27 – Jul 4 |
| Summer squash | Sow outdoors | May 13 – Jun 27 |
| Winter squash & pumpkins | Sow outdoors | May 27 – Jun 27 |
| Snap beans | Sow outdoors | May 13 – Jul 27 |
| Sweet corn | Sow outdoors | May 13 – Jun 24 |
| Watermelon & cantaloupe | Sow outdoors | May 27 – Jun 27 |
| Okra | Sow outdoors | May 20 – Jun 12 |
| Peas | Sow outdoors (spring) | Mar 27 – May 12 |
| Potatoes | Plant outdoors (spring) | Mar 27 – May 27 |
| Onions | Start seeds indoors (spring) | Feb 13 – Mar 12 |
| Onions | Transplant outdoors (spring) | Apr 13 – May 12 |
| Broccoli | Start seeds indoors (spring) | Mar 9 – Apr 12 |
| Broccoli | Transplant outdoors (spring) | Apr 13 – May 12 |
| Broccoli | Start seeds indoors (fall) | Jun 14 – Jun 24 |
| Broccoli | Transplant outdoors (fall) | Jul 14 – Jul 25 |
| Cabbage | Start seeds indoors (spring) | Feb 27 – Mar 27 |
| Cabbage | Transplant outdoors (spring) | Mar 27 – Apr 27 |
| Cabbage | Start seeds indoors (fall) | Jun 4 – Jul 4 |
| Cabbage | Transplant outdoors (fall) | Jul 4 – Aug 4 |
| Leaf lettuce | Sow outdoors (spring) | Mar 27 – Jun 12 |
| Leaf lettuce | Sow outdoors (fall) | Jul 4 – Aug 20 |
| Spinach | Sow outdoors (spring) | Mar 20 – May 3 |
| Spinach | Sow outdoors (fall) | Jul 21 – Aug 25 |
| Radishes | Sow outdoors (spring) | Mar 27 – May 17 |
| Radishes | Sow outdoors (fall) | Jul 4 – Sep 4 |
| Kale | Sow outdoors (spring) | Apr 13 – May 3 |
| Kale | Sow outdoors (fall) | Jun 27 – Aug 4 |
| Carrots | Sow outdoors (spring) | Apr 27 – Jun 12 |
| Carrots | Sow outdoors (fall) | Jun 4 – Jul 20 |
| Garlic | Plant outdoors (fall) | Oct 4 – Nov 4 |
Where these dates come from
ZIP code 53570 is matched to the NOAA station Monroe Wwtp, WI, 16.5 km away, at 991 ft elevation (102 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Monroe Wwtp, WI (used) | 991 ft | Apr 27 | Oct 14 |
| Brodhead Wwtp, WI | 780 ft | Apr 29 | Oct 12 |
| Uw Arboretum - Madison, WI | 870 ft | May 1 | Oct 9 |
| Charmany Farm, WI | 1,046 ft | Apr 28 | Oct 15 |
Frost dates near Monticello
- New Glarus, WI 53574 · last Apr 27, first Oct 14
- Albany, WI 53502 · last Apr 29, first Oct 12
- Belleville, WI 53508 · last May 1, first Oct 9
- Monroe, WI 53566 · last Apr 27, first Oct 14
- Juda, WI 53550 · last Apr 29, first Oct 12
- Argyle, WI 53504 · last May 3, first Oct 4
- Blanchardville, WI 53516 · last May 3, first Oct 4
- Brooklyn, WI 53521 · last Apr 30, first Oct 11
Frequently asked questions
- When is the last frost in Monticello, WI?
- For ZIP code 53570, the average last spring frost (32°F) is April 27, based on NOAA 1991-2020 climate normals for the Monroe Wwtp, WI weather station. There is a 1-in-10 chance of a frost after May 12.
- When is the first frost in Monticello, WI?
- The average first fall frost (32°F) is October 14. There is a 1-in-10 chance of frost by September 29, so tender plants are at risk from that point on.
- How long is the growing season in 53570?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 170 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.