Altoona, WI frost dates
Last spring frostApr 24median date
First fall frostOct 14median date
Growing season173 daysfrost-free
Hardiness zone4bZone 4b
How Altoona compares
- In 8 years out of 10, the last spring frost in Altoona falls between April 9 and May 7, a 28-day window. The first fall frost falls between September 26 and October 28.
- The median last frost is 11 days earlier than the Wisconsin median of May 5.
- Its 173-day growing season is longer than 89% of the 749 Wisconsin places with a regular frost season (state median 155 days).
- The last frost is 14 days earlier than the zone 4b median of May 8. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 4b chart.
- The weather station records an average of 149 nights a year at or below 32°F.
- Altoona shares its weather station with Eau Claire, WI, 5 km away, so the two have the same frost dates.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 9 |
| 50% (median) | April 24 |
| 10% (safe for tender plants) | May 7 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 26 |
| 50% (median) | October 14 |
| 90% (late) | October 28 |
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 Altoona, WI
Altoona, WI frost dates — last frost Apr 24, first frost Oct 14, zone 4b. whenisthelastfrost.com
Crop
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Start indoors: Jan 30 to Feb 13Transplant outside: Mar 27 to Apr 10
Start indoors: Feb 13 to Feb 27Transplant outside: May 8 to May 22
Start indoors: Feb 13 to Feb 27Transplant outside: May 8 to May 22
Start indoors: Feb 27 to Mar 13Transplant outside: May 1 to May 15
Start indoors: Feb 27 to Mar 13Transplant outside: Apr 3 to Apr 17Sow outdoors: Mar 27 to May 1Plant for fall: Aug 19 to Sep 16
Start indoors: Feb 27 to Mar 13Transplant outside: Mar 27 to Apr 10Sow outdoors: Mar 27 to Apr 10Plant for fall: Aug 5 to Aug 26
Start indoors: Feb 27 to Mar 13Transplant outside: Apr 10 to Apr 24Plant for fall: Jul 8 to Jul 29
Start indoors: Feb 27 to Mar 13Transplant outside: Apr 3 to Apr 17Plant for fall: Jul 8 to Jul 29
Start indoors: Feb 27 to Mar 13Transplant outside: Apr 10 to Apr 24Plant for fall: Jul 8 to Jul 29
Start indoors: Mar 13 to Mar 27Transplant outside: May 15 to May 29Sow outdoors: May 15 to May 29
Start indoors: Mar 13 to Mar 27Transplant outside: May 1 to May 15
Sow outdoors: Mar 13 to Apr 3Plant for fall: Jul 22 to Aug 12
Sow outdoors: Mar 13 to Apr 3Plant for fall: Aug 19 to Sep 9
Sow outdoors: Mar 20 to May 1Plant for fall: Sep 2 to Sep 23
Start indoors: Mar 27 to Apr 3Transplant outside: May 8 to May 15Sow outdoors: May 1 to May 15Plant for fall: Jul 29 to Aug 12
Start indoors: Mar 27 to Apr 3Sow outdoors: May 1 to May 15Plant for fall: Aug 5 to Aug 19
Start indoors: Mar 27 to Apr 3Sow outdoors: May 1 to May 15
Start indoors: Mar 27 to Apr 3Transplant outside: May 8 to May 22
Sow outdoors: Apr 3 to May 1Plant for fall: Jul 22 to Aug 5
Sow outdoors: Apr 3 to May 1Plant for fall: Aug 5 to Aug 19
Sow outdoors: Apr 3 to Apr 24
Sow outdoors: Apr 10 to May 8Plant for fall: Aug 5 to Aug 19
Sow outdoors: Apr 10 to May 1Plant for fall: Aug 19 to Sep 9
Sow outdoors: May 1 to May 22Plant for fall: Jul 29 to Aug 12
Sow outdoors: May 1 to May 15
Transplant outside: May 8 to May 29
Plant for fall: Sep 30 to Nov 4
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Altoona, WI
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 30 – Feb 13 | Mar 27 – Apr 10 | — | — |
| Peppers | Feb 13 – Feb 27 | May 8 – May 22 | — | — |
| Eggplant | Feb 13 – Feb 27 | May 8 – May 22 | — | — |
| Tomatoes | Feb 27 – Mar 13 | May 1 – May 15 | — | — |
| Lettuce | Feb 27 – Mar 13 | Apr 3 – Apr 17 | Mar 27 – May 1 | Aug 19 – Sep 16 |
| Kale | Feb 27 – Mar 13 | Mar 27 – Apr 10 | Mar 27 – Apr 10 | Aug 5 – Aug 26 |
| Broccoli | Feb 27 – Mar 13 | Apr 10 – Apr 24 | — | Jul 8 – Jul 29 |
| Cabbage | Feb 27 – Mar 13 | Apr 3 – Apr 17 | — | Jul 8 – Jul 29 |
| Cauliflower | Feb 27 – Mar 13 | Apr 10 – Apr 24 | — | Jul 8 – Jul 29 |
| Okra | Mar 13 – Mar 27 | May 15 – May 29 | May 15 – May 29 | — |
| Basil | Mar 13 – Mar 27 | May 1 – May 15 | — | — |
| Peas | — | — | Mar 13 – Apr 3 | Jul 22 – Aug 12 |
| Spinach | — | — | Mar 13 – Apr 3 | Aug 19 – Sep 9 |
| Radishes | — | — | Mar 20 – May 1 | Sep 2 – Sep 23 |
| Cucumbers | Mar 27 – Apr 3 | May 8 – May 15 | May 1 – May 15 | Jul 29 – Aug 12 |
| Zucchini & Summer Squash | Mar 27 – Apr 3 | — | May 1 – May 15 | Aug 5 – Aug 19 |
| Winter Squash & Pumpkins | Mar 27 – Apr 3 | — | May 1 – May 15 | — |
| Melons & Watermelon | Mar 27 – Apr 3 | May 8 – May 22 | — | — |
| Carrots | — | — | Apr 3 – May 1 | Jul 22 – Aug 5 |
| Beets | — | — | Apr 3 – May 1 | Aug 5 – Aug 19 |
| Potatoes | — | — | Apr 3 – Apr 24 | — |
| Swiss Chard | — | — | Apr 10 – May 8 | Aug 5 – Aug 19 |
| Cilantro | — | — | Apr 10 – May 1 | Aug 19 – Sep 9 |
| Green Beans | — | — | May 1 – May 22 | Jul 29 – Aug 12 |
| Sweet Corn | — | — | May 1 – May 15 | — |
| Sweet Potatoes | — | May 8 – May 29 | — | — |
| Garlic | — | — | — | Sep 30 – Nov 4 |
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 Eau Claire 3sw, WI weather station, 6 km away (elevation 879 ft (268 m)).
Frost dates near Altoona
- Eau Claire Apr 24 · Oct 14
- Fall Creek May 7 · Oct 1
- Chippewa Falls May 8 · Oct 4
- Elk Mound May 8 · Oct 4
- Rock Falls Apr 24 · Oct 14
- Eleva May 10 · Oct 2
- Strum May 10 · Oct 2
- Augusta May 7 · Oct 1
- Cadott May 1 · Oct 8
- Osseo May 7 · Oct 1
Frequently asked questions
When is the last frost in Altoona, WI?
The median last spring frost in Altoona, WI is April 24. There is still about a 10% chance of frost after May 7, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Altoona, WI?
The median first fall frost is October 14, with about a 10% chance of frost before September 26.
How long is the growing season in Altoona, WI?
About 173 days between the median last spring frost and first fall frost.
What planting zone is Altoona, WI?
Altoona, WI is in USDA hardiness zone 4b.