Frost dates for 53137Helenville, WI
The average last spring frost in Helenville is April 25 and the average first fall frost is October 18, giving a typical growing season of about 173 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 25
- Average first fall frost
- Oct 18
- Growing season
- 173 days
Safer after May 9 (1-in-10 risk)
Possible by Oct 2 (1-in-10 risk)
Last frost typically in 174 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 20 | Sep 23 · Oct 5 · Oct 20 | 153 days | 100% |
| Frost / freeze (32°F) | Apr 12 · Apr 25 · May 9 | Oct 2 · Oct 18 · Oct 31 | 173 days | 100% |
| Hard freeze (28°F) | Apr 2 · Apr 15 · Apr 29 | Oct 15 · Oct 29 · Nov 10 | 195 days | 100% |
Planting calendar for Helenville
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 25 – May 31 |
| Tomatoes | Transplant outdoors | May 11 – Jun 28 |
| Peppers | Start seeds indoors | Mar 25 – Apr 25 |
| Peppers | Transplant outdoors | May 25 – Jun 25 |
| Eggplant | Start seeds indoors | Apr 11 – May 10 |
| Eggplant | Transplant outdoors | May 25 – Jun 25 |
| Cucumbers | Sow outdoors | May 25 – Jul 8 |
| Summer squash | Sow outdoors | May 11 – Jun 25 |
| Winter squash & pumpkins | Sow outdoors | May 25 – Jun 25 |
| Snap beans | Sow outdoors | May 11 – Jul 31 |
| Sweet corn | Sow outdoors | May 11 – Jun 28 |
| Watermelon & cantaloupe | Sow outdoors | May 25 – Jun 25 |
| Okra | Sow outdoors | May 18 – Jun 10 |
| Peas | Sow outdoors (spring) | Mar 25 – May 10 |
| Potatoes | Plant outdoors (spring) | Mar 25 – May 25 |
| Onions | Start seeds indoors (spring) | Feb 11 – Mar 10 |
| Onions | Transplant outdoors (spring) | Apr 11 – May 10 |
| Broccoli | Start seeds indoors (spring) | Mar 7 – Apr 10 |
| Broccoli | Transplant outdoors (spring) | Apr 11 – May 10 |
| Broccoli | Start seeds indoors (fall) | Jun 18 – Jun 28 |
| Broccoli | Transplant outdoors (fall) | Jul 18 – Jul 29 |
| Cabbage | Start seeds indoors (spring) | Feb 25 – Mar 25 |
| Cabbage | Transplant outdoors (spring) | Mar 25 – Apr 25 |
| Cabbage | Start seeds indoors (fall) | Jun 8 – Jul 8 |
| Cabbage | Transplant outdoors (fall) | Jul 8 – Aug 8 |
| Leaf lettuce | Sow outdoors (spring) | Mar 25 – Jun 10 |
| Leaf lettuce | Sow outdoors (fall) | Jul 8 – Aug 24 |
| Spinach | Sow outdoors (spring) | Mar 18 – May 1 |
| Spinach | Sow outdoors (fall) | Jul 25 – Aug 29 |
| Radishes | Sow outdoors (spring) | Mar 25 – May 15 |
| Radishes | Sow outdoors (fall) | Jul 8 – Sep 8 |
| Kale | Sow outdoors (spring) | Apr 11 – May 1 |
| Kale | Sow outdoors (fall) | Jul 1 – Aug 8 |
| Carrots | Sow outdoors (spring) | Apr 25 – Jun 10 |
| Carrots | Sow outdoors (fall) | Jun 8 – Jul 24 |
| Garlic | Plant outdoors (fall) | Oct 8 – Nov 8 |
Where these dates come from
ZIP code 53137 is matched to the NOAA station Jefferson Wwtp, WI, 10.8 km away, at 783 ft elevation (47 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Jefferson Wwtp, WI (used) | 783 ft | Apr 25 | Oct 18 |
| Sullivan 3Se, WI | 933 ft | May 3 | Oct 9 |
| Oconomowoc Wwtp, WI | 858 ft | Apr 30 | Oct 12 |
| Whitewater, WI | 875 ft | May 2 | Oct 9 |
Frost dates near Helenville
- Sullivan, WI 53178 · last May 3, first Oct 9
- Jefferson, WI 53549 · last Apr 25, first Oct 18
- Johnson Creek, WI 53038 · last Apr 29, first Oct 14
- Palmyra, WI 53156 · last May 2, first Oct 9
- Dousman, WI 53118 · last Apr 30, first Oct 12
- Ixonia, WI 53036 · last Apr 30, first Oct 12
- Fort Atkinson, WI 53538 · last Apr 28, first Oct 13
- Oconomowoc, WI 53066 · last Apr 30, first Oct 12
Frequently asked questions
- When is the last frost in Helenville, WI?
- For ZIP code 53137, the average last spring frost (32°F) is April 25, based on NOAA 1991-2020 climate normals for the Jefferson Wwtp, WI weather station. There is a 1-in-10 chance of a frost after May 9.
- When is the first frost in Helenville, WI?
- The average first fall frost (32°F) is October 18. There is a 1-in-10 chance of frost by October 2, so tender plants are at risk from that point on.
- How long is the growing season in 53137?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 173 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.