Whitewater, WI planting zone & frost dates
Whitewater is in USDA hardiness zone 5b. The last spring frost usually comes around May 2 and the first fall frost around October 9, for a growing season of about 157 days.
Planting calendar for Whitewater
Dates are counted from the average last spring frost (May 2) 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: Mar 7 – Mar 21 Transplant outdoors: May 9 – May 16 |
| Peppers | Start seeds indoors: Feb 21 – Mar 7 Transplant outdoors: May 16 – May 23 |
| Eggplant | Start seeds indoors: Feb 21 – Mar 7 Transplant outdoors: May 16 – May 23 |
| Broccoli | Start seeds indoors: Feb 21 – Mar 7 Transplant outdoors: Apr 4 – Apr 18 |
| Cabbage | Start seeds indoors: Feb 21 – Mar 7 Transplant outdoors: Apr 4 – Apr 18 |
| Onions (sets) | Plant outdoors: Apr 4 – Apr 18 |
| Peas | Sow outdoors: Mar 21 – Apr 4 |
| Spinach | Sow outdoors: Mar 21 – Apr 4 |
| Lettuce | Sow outdoors: Apr 4 – Apr 18 |
| Carrots | Sow outdoors: Apr 4 – Apr 18 |
| Potatoes | Plant outdoors: Apr 4 – Apr 18 |
| Beans | Sow outdoors: May 9 – May 16 |
| Sweet corn | Sow outdoors: May 9 – May 16 |
| Cucumbers | Sow outdoors: May 9 – May 16 |
| Squash & zucchini | Sow outdoors: May 9 – May 16 |
| Basil | Start seeds indoors: Mar 21 – Apr 4 Transplant outdoors: May 9 – May 16 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 14 (8 weeks before the average first fall frost on Oct 9).
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 18 | May 2 | May 20 |
| First 32°F frost in fall is before | Oct 24 | Oct 9 | Sep 25 |
How to read it: in spring there is a 10% chance of a frost after May 20, so that is a safe date for tender plants. In fall there is a 10% chance of frost before September 25. A hard freeze (28°F) usually ends around April 20.
Hardiness zone by ZIP code in Whitewater
- 53190 zone 5b
Nearby cities
- Fort Atkinson zone 5b, last frost Apr 28
- Janesville zone 5b, last frost Apr 26
- Watertown zone 5b, last frost Apr 28
- Oconomowoc zone 5b, last frost Apr 30
- Beloit zone 5b, last frost May 1
- Burlington zone 5b, last frost May 5
- Stoughton zone 5b, last frost Apr 30
- Waukesha zone 5b, last frost May 1
Questions
What growing zone is Whitewater, WI?
Whitewater 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 Whitewater?
The average last spring frost (32°F) in Whitewater is May 2. There is still a 10% chance of frost until May 20.
When can I plant tomatoes in Whitewater?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around May 9 – May 16. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Whitewater, WI (USC00479190), 2.0 km (1.2 mi) from the city center, elevation 267 m, based on 30 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.