Oshkosh, WI planting zone & frost dates
Oshkosh is in USDA hardiness zone 5b. The last spring frost usually comes around April 24 and the first fall frost around October 20, for a growing season of about 178 days.
Planting calendar for Oshkosh
Dates are counted from the average last spring frost (April 24) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.
| Crop | When |
|---|---|
| Tomatoes | Start seeds indoors: Feb 27 – Mar 13 Transplant outdoors: May 1 – May 8 |
| Peppers | Start seeds indoors: Feb 13 – Feb 27 Transplant outdoors: May 8 – May 15 |
| Eggplant | Start seeds indoors: Feb 13 – Feb 27 Transplant outdoors: May 8 – May 15 |
| Broccoli | Start seeds indoors: Feb 13 – Feb 27 Transplant outdoors: Mar 27 – Apr 10 |
| Cabbage | Start seeds indoors: Feb 13 – Feb 27 Transplant outdoors: Mar 27 – Apr 10 |
| Onions (sets) | Plant outdoors: Mar 27 – Apr 10 |
| Peas | Sow outdoors: Mar 13 – Mar 27 |
| Spinach | Sow outdoors: Mar 13 – Mar 27 |
| Lettuce | Sow outdoors: Mar 27 – Apr 10 |
| Carrots | Sow outdoors: Mar 27 – Apr 10 |
| Potatoes | Plant outdoors: Mar 27 – Apr 10 |
| Beans | Sow outdoors: May 1 – May 8 |
| Sweet corn | Sow outdoors: May 1 – May 8 |
| Cucumbers | Sow outdoors: May 1 – May 8 |
| Squash & zucchini | Sow outdoors: May 1 – May 8 |
| Basil | Start seeds indoors: Mar 13 – Mar 27 Transplant outdoors: May 1 – May 8 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 25 (8 weeks before the average first fall frost on Oct 20).
Useful for zone 5b gardens
- Seed starting kit with dome — to start seeds indoors before the last frost
- LED grow light for seedlings — stops leggy seedlings
- Frost cloth / plant covers — for late spring and early fall frosts
- Soil thermometer — warm-season crops need soil above 60°F
- Cold frame / mini greenhouse — adds weeks to a short season
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Apr 10 | Apr 24 | May 8 |
| First 32°F frost in fall is before | Nov 2 | Oct 20 | Oct 4 |
How to read it: in spring there is a 10% chance of a frost after May 8, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 4. A hard freeze (28°F) usually ends around April 13.
Hardiness zone by ZIP code in Oshkosh
- 54901 zone 5b
- 54902 zone 5b
- 54903 zone 5b
- 54904 zone 5b
- 54906 zone 5b
Nearby cities
- Neenah zone 5b, last frost May 4
- Menasha zone 5b, last frost May 4
- Appleton zone 5b, last frost May 4
- Fond du Lac zone 5b, last frost Apr 27
- Little Chute zone 5b, last frost May 4
- Kaukauna zone 5b, last frost May 4
- Waupun zone 5a, last frost May 1
- Beaver Dam zone 5a, last frost May 2
Questions
What growing zone is Oshkosh, WI?
Oshkosh is in USDA Plant Hardiness Zone 5b (average extreme winter low -15°F to -10°F), according to the USDA 2023 map.
When is the last frost in Oshkosh?
The average last spring frost (32°F) in Oshkosh is April 24. There is still a 10% chance of frost until May 8.
When can I plant tomatoes in Oshkosh?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around May 1 – May 8. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Oshkosh, WI (USC00476330), 1.3 km (0.8 mi) from the city center, elevation 229 m, based on 29 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.