River Falls, WI frost dates
Last spring frostMay 11median date
First fall frostOct 1median date
Growing season143 daysfrost-free
Hardiness zone4bZone 4b
How River Falls compares
- In 8 years out of 10, the last spring frost in River Falls falls between April 26 and May 26, a 30-day window. The first fall frost falls between September 19 and October 15.
- The median last frost is 6 days later than the Wisconsin median of May 5.
- Its 143-day growing season is longer than 20% of the 749 Wisconsin places with a regular frost season (state median 155 days).
- The last frost is typical for zone 4b, where the median is May 8.
- The weather station records an average of 170 nights a year at or below 32°F.
- Compared with Saint Paul, MN, 39 km away, the last frost here is 17 days later than there and the growing season is 32 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 26 |
| 50% (median) | May 11 |
| 10% (safe for tender plants) | May 26 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 19 |
| 50% (median) | October 1 |
| 90% (late) | October 15 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for River Falls, WI
River Falls, WI frost dates — last frost May 11, first frost Oct 1, zone 4b. whenisthelastfrost.com
Crop
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Start indoors: Feb 16 to Mar 2Transplant outside: Apr 13 to Apr 27
Start indoors: Mar 2 to Mar 16Transplant outside: May 25 to Jun 8
Start indoors: Mar 2 to Mar 16Transplant outside: May 25 to Jun 8
Start indoors: Mar 16 to Mar 30Transplant outside: May 18 to Jun 1
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 20 to May 4Sow outdoors: Apr 13 to May 18Plant for fall: Aug 6 to Sep 3
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 13 to Apr 27Sow outdoors: Apr 13 to Apr 27Plant for fall: Jul 23 to Aug 13
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 27 to May 11Plant for fall: Jun 25 to Jul 16
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 20 to May 4Plant for fall: Jun 25 to Jul 16
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 27 to May 11Plant for fall: Jun 25 to Jul 16
Start indoors: Mar 30 to Apr 13Transplant outside: Jun 1 to Jun 15Sow outdoors: Jun 1 to Jun 15
Start indoors: Mar 30 to Apr 13Transplant outside: May 18 to Jun 1
Sow outdoors: Mar 30 to Apr 20Plant for fall: Jul 9 to Jul 30
Sow outdoors: Mar 30 to Apr 20Plant for fall: Aug 6 to Aug 27
Sow outdoors: Apr 6 to May 18Plant for fall: Aug 20 to Sep 10
Start indoors: Apr 13 to Apr 20Transplant outside: May 25 to Jun 1Sow outdoors: May 18 to Jun 1Plant for fall: Jul 16 to Jul 30
Start indoors: Apr 13 to Apr 20Sow outdoors: May 18 to Jun 1Plant for fall: Jul 23 to Aug 6
Start indoors: Apr 13 to Apr 20Sow outdoors: May 18 to Jun 1
Start indoors: Apr 13 to Apr 20Transplant outside: May 25 to Jun 8
Sow outdoors: Apr 20 to May 18Plant for fall: Jul 9 to Jul 23
Sow outdoors: Apr 20 to May 18Plant for fall: Jul 23 to Aug 6
Sow outdoors: Apr 20 to May 11
Sow outdoors: Apr 27 to May 25Plant for fall: Jul 23 to Aug 6
Sow outdoors: Apr 27 to May 18Plant for fall: Aug 6 to Aug 27
Sow outdoors: May 18 to Jun 8Plant for fall: Jul 16 to Jul 30
Sow outdoors: May 18 to Jun 1
Transplant outside: May 25 to Jun 15
Plant for fall: Sep 17 to Oct 22
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in River Falls, WI
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 16 – Mar 2 | Apr 13 – Apr 27 | — | — |
| Peppers | Mar 2 – Mar 16 | May 25 – Jun 8 | — | — |
| Eggplant | Mar 2 – Mar 16 | May 25 – Jun 8 | — | — |
| Tomatoes | Mar 16 – Mar 30 | May 18 – Jun 1 | — | — |
| Lettuce | Mar 16 – Mar 30 | Apr 20 – May 4 | Apr 13 – May 18 | Aug 6 – Sep 3 |
| Kale | Mar 16 – Mar 30 | Apr 13 – Apr 27 | Apr 13 – Apr 27 | Jul 23 – Aug 13 |
| Broccoli | Mar 16 – Mar 30 | Apr 27 – May 11 | — | Jun 25 – Jul 16 |
| Cabbage | Mar 16 – Mar 30 | Apr 20 – May 4 | — | Jun 25 – Jul 16 |
| Cauliflower | Mar 16 – Mar 30 | Apr 27 – May 11 | — | Jun 25 – Jul 16 |
| Okra | Mar 30 – Apr 13 | Jun 1 – Jun 15 | Jun 1 – Jun 15 | — |
| Basil | Mar 30 – Apr 13 | May 18 – Jun 1 | — | — |
| Peas | — | — | Mar 30 – Apr 20 | Jul 9 – Jul 30 |
| Spinach | — | — | Mar 30 – Apr 20 | Aug 6 – Aug 27 |
| Radishes | — | — | Apr 6 – May 18 | Aug 20 – Sep 10 |
| Cucumbers | Apr 13 – Apr 20 | May 25 – Jun 1 | May 18 – Jun 1 | Jul 16 – Jul 30 |
| Zucchini & Summer Squash | Apr 13 – Apr 20 | — | May 18 – Jun 1 | Jul 23 – Aug 6 |
| Winter Squash & Pumpkins | Apr 13 – Apr 20 | — | May 18 – Jun 1 | — |
| Melons & Watermelon | Apr 13 – Apr 20 | May 25 – Jun 8 | — | — |
| Carrots | — | — | Apr 20 – May 18 | Jul 9 – Jul 23 |
| Beets | — | — | Apr 20 – May 18 | Jul 23 – Aug 6 |
| Potatoes | — | — | Apr 20 – May 11 | — |
| Swiss Chard | — | — | Apr 27 – May 25 | Jul 23 – Aug 6 |
| Cilantro | — | — | Apr 27 – May 18 | Aug 6 – Aug 27 |
| Green Beans | — | — | May 18 – Jun 8 | Jul 16 – Jul 30 |
| Sweet Corn | — | — | May 18 – Jun 1 | — |
| Sweet Potatoes | — | May 25 – Jun 15 | — | — |
| Garlic | — | — | — | Sep 17 – Oct 22 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the River Falls, WI weather station, about 1 km away (elevation 942 ft (287 m)).
Frost dates near River Falls
- Prescott Apr 23 · Oct 19
- Roberts May 6 · Oct 2
- Hudson Apr 22 · Oct 19
- Ellsworth May 13 · Sep 29
- Beldenville May 13 · Sep 29
- East Ellsworth May 13 · Sep 29
- Hammond May 6 · Oct 2
- Baldwin May 6 · Oct 2
- Houlton Apr 22 · Oct 19
- Hager City Apr 23 · Oct 14
Frequently asked questions
When is the last frost in River Falls, WI?
The median last spring frost in River Falls, WI is May 11. There is still about a 10% chance of frost after May 26, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in River Falls, WI?
The median first fall frost is October 1, with about a 10% chance of frost before September 19.
How long is the growing season in River Falls, WI?
About 143 days between the median last spring frost and first fall frost.
What planting zone is River Falls, WI?
River Falls, WI is in USDA hardiness zone 4b.