Frost dates for 54902Oshkosh, WI
The average last spring frost in Oshkosh is April 24 and the average first fall frost is October 20, giving a typical growing season of about 178 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 24
- Average first fall frost
- Oct 20
- Growing season
- 178 days
Safer after May 8 (1-in-10 risk)
Possible by Oct 4 (1-in-10 risk)
Last frost typically in 179 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 20 · May 4 · May 19 | Sep 24 · Oct 6 · Oct 22 | 155 days | 100% |
| Frost / freeze (32°F) | Apr 10 · Apr 24 · May 8 | Oct 4 · Oct 20 · Nov 2 | 178 days | 100% |
| Hard freeze (28°F) | Mar 31 · Apr 13 · Apr 26 | Oct 17 · Oct 31 · Nov 13 | 200 days | 100% |
Planting calendar for Oshkosh
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 24 – May 30 |
| Tomatoes | Transplant outdoors | May 10 – Jun 30 |
| Peppers | Start seeds indoors | Mar 24 – Apr 24 |
| Peppers | Transplant outdoors | May 24 – Jun 24 |
| Eggplant | Start seeds indoors | Apr 10 – May 9 |
| Eggplant | Transplant outdoors | May 24 – Jun 24 |
| Cucumbers | Sow outdoors | May 24 – Jul 10 |
| Summer squash | Sow outdoors | May 10 – Jun 24 |
| Winter squash & pumpkins | Sow outdoors | May 24 – Jun 24 |
| Snap beans | Sow outdoors | May 10 – Aug 2 |
| Sweet corn | Sow outdoors | May 10 – Jun 30 |
| Watermelon & cantaloupe | Sow outdoors | May 24 – Jun 24 |
| Okra | Sow outdoors | May 17 – Jun 9 |
| Peas | Sow outdoors (spring) | Mar 24 – May 9 |
| Potatoes | Plant outdoors (spring) | Mar 24 – May 24 |
| Onions | Start seeds indoors (spring) | Feb 10 – Mar 9 |
| Onions | Transplant outdoors (spring) | Apr 10 – May 9 |
| Broccoli | Start seeds indoors (spring) | Mar 6 – Apr 9 |
| Broccoli | Transplant outdoors (spring) | Apr 10 – May 9 |
| Broccoli | Start seeds indoors (fall) | Jun 20 – Jun 30 |
| Broccoli | Transplant outdoors (fall) | Jul 20 – Jul 31 |
| Cabbage | Start seeds indoors (spring) | Feb 24 – Mar 24 |
| Cabbage | Transplant outdoors (spring) | Mar 24 – Apr 24 |
| Cabbage | Start seeds indoors (fall) | Jun 10 – Jul 10 |
| Cabbage | Transplant outdoors (fall) | Jul 10 – Aug 10 |
| Leaf lettuce | Sow outdoors (spring) | Mar 24 – Jun 9 |
| Leaf lettuce | Sow outdoors (fall) | Jul 10 – Aug 26 |
| Spinach | Sow outdoors (spring) | Mar 17 – Apr 30 |
| Spinach | Sow outdoors (fall) | Jul 27 – Aug 31 |
| Radishes | Sow outdoors (spring) | Mar 24 – May 14 |
| Radishes | Sow outdoors (fall) | Jul 10 – Sep 10 |
| Kale | Sow outdoors (spring) | Apr 10 – Apr 30 |
| Kale | Sow outdoors (fall) | Jul 3 – Aug 10 |
| Carrots | Sow outdoors (spring) | Apr 24 – Jun 9 |
| Carrots | Sow outdoors (fall) | Jun 10 – Jul 26 |
| Garlic | Plant outdoors (fall) | Oct 10 – Nov 10 |
Where these dates come from
ZIP code 54902 is matched to the NOAA station Oshkosh, WI, 3.9 km away, at 750 ft elevation (5 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Oshkosh, WI (used) | 750 ft | Apr 24 | Oct 20 |
| Oshkosh Wittman Ap, WI | 782 ft | Apr 30 | Oct 13 |
| Ripon 5 Ne, WI | 930 ft | May 1 | Oct 11 |
| Fond Du Lac Wwtp, WI | 750 ft | May 1 | Oct 12 |
Frost dates near Oshkosh
- Oshkosh, WI 54901 · last Apr 24, first Oct 20
- Winnebago, WI 54985 · last Apr 24, first Oct 20
- Van Dyne, WI 54979 · last May 1, first Oct 12
- Butte Des Morts, WI 54927 · last Apr 24, first Oct 20
- Pickett, WI 54964 · last May 1, first Oct 11
- Omro, WI 54963 · last May 1, first Oct 8
- Eldorado, WI 54932 · last May 1, first Oct 10
- Waukau, WI 54980 · last May 1, first Oct 8
Frequently asked questions
- When is the last frost in Oshkosh, WI?
- For ZIP code 54902, the average last spring frost (32°F) is April 24, based on NOAA 1991-2020 climate normals for the Oshkosh, WI weather station. There is a 1-in-10 chance of a frost after May 8.
- When is the first frost in Oshkosh, WI?
- The average first fall frost (32°F) is October 20. There is a 1-in-10 chance of frost by October 4, so tender plants are at risk from that point on.
- How long is the growing season in 54902?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 178 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.