Humboldt, SD frost dates
Last spring frostMay 7median date
First fall frostSep 29median date
Growing season145 daysfrost-free
Hardiness zone4bZone 4b
How Humboldt compares
- In 8 years out of 10, the last spring frost in Humboldt falls between April 25 and May 19, a 24-day window. The first fall frost falls between September 17 and October 13.
- The median last frost is 1 day later than the South Dakota median of May 6.
- Its 145-day growing season is longer than 31% of the 363 South Dakota places with a regular frost season (state median 149 days).
- The last frost is typical for zone 4b, where the median is May 8.
- The weather station records an average of 169 nights a year at or below 32°F.
- Compared with Sioux Falls, SD, 26 km away, the last frost here is 11 days later than there and the growing season is 25 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 25 |
| 50% (median) | May 7 |
| 10% (safe for tender plants) | May 19 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 17 |
| 50% (median) | September 29 |
| 90% (late) | October 13 |
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 Humboldt, SD
Humboldt, SD frost dates — last frost May 7, first frost Sep 29, zone 4b. whenisthelastfrost.com
Crop
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Start indoors: Feb 12 to Feb 26Transplant outside: Apr 9 to Apr 23
Start indoors: Feb 26 to Mar 12Transplant outside: May 21 to Jun 4
Start indoors: Feb 26 to Mar 12Transplant outside: May 21 to Jun 4
Start indoors: Mar 12 to Mar 26Transplant outside: May 14 to May 28
Start indoors: Mar 12 to Mar 26Transplant outside: Apr 16 to Apr 30Sow outdoors: Apr 9 to May 14Plant for fall: Aug 4 to Sep 1
Start indoors: Mar 12 to Mar 26Transplant outside: Apr 9 to Apr 23Sow outdoors: Apr 9 to Apr 23Plant for fall: Jul 21 to Aug 11
Start indoors: Mar 12 to Mar 26Transplant outside: Apr 23 to May 7Plant for fall: Jun 23 to Jul 14
Start indoors: Mar 12 to Mar 26Transplant outside: Apr 16 to Apr 30Plant for fall: Jun 23 to Jul 14
Start indoors: Mar 12 to Mar 26Transplant outside: Apr 23 to May 7Plant for fall: Jun 23 to Jul 14
Start indoors: Mar 26 to Apr 9Transplant outside: May 28 to Jun 11Sow outdoors: May 28 to Jun 11
Start indoors: Mar 26 to Apr 9Transplant outside: May 14 to May 28
Sow outdoors: Mar 26 to Apr 16Plant for fall: Jul 7 to Jul 28
Sow outdoors: Mar 26 to Apr 16Plant for fall: Aug 4 to Aug 25
Sow outdoors: Apr 2 to May 14Plant for fall: Aug 18 to Sep 8
Start indoors: Apr 9 to Apr 16Transplant outside: May 21 to May 28Sow outdoors: May 14 to May 28Plant for fall: Jul 14 to Jul 28
Start indoors: Apr 9 to Apr 16Sow outdoors: May 14 to May 28Plant for fall: Jul 21 to Aug 4
Start indoors: Apr 9 to Apr 16Sow outdoors: May 14 to May 28
Start indoors: Apr 9 to Apr 16Transplant outside: May 21 to Jun 4
Sow outdoors: Apr 16 to May 14Plant for fall: Jul 7 to Jul 21
Sow outdoors: Apr 16 to May 14Plant for fall: Jul 21 to Aug 4
Sow outdoors: Apr 16 to May 7
Sow outdoors: Apr 23 to May 21Plant for fall: Jul 21 to Aug 4
Sow outdoors: Apr 23 to May 14Plant for fall: Aug 4 to Aug 25
Sow outdoors: May 14 to Jun 4Plant for fall: Jul 14 to Jul 28
Sow outdoors: May 14 to May 28
Transplant outside: May 21 to Jun 11
Plant for fall: Sep 15 to Oct 20
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Humboldt, SD
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 12 – Feb 26 | Apr 9 – Apr 23 | — | — |
| Peppers | Feb 26 – Mar 12 | May 21 – Jun 4 | — | — |
| Eggplant | Feb 26 – Mar 12 | May 21 – Jun 4 | — | — |
| Tomatoes | Mar 12 – Mar 26 | May 14 – May 28 | — | — |
| Lettuce | Mar 12 – Mar 26 | Apr 16 – Apr 30 | Apr 9 – May 14 | Aug 4 – Sep 1 |
| Kale | Mar 12 – Mar 26 | Apr 9 – Apr 23 | Apr 9 – Apr 23 | Jul 21 – Aug 11 |
| Broccoli | Mar 12 – Mar 26 | Apr 23 – May 7 | — | Jun 23 – Jul 14 |
| Cabbage | Mar 12 – Mar 26 | Apr 16 – Apr 30 | — | Jun 23 – Jul 14 |
| Cauliflower | Mar 12 – Mar 26 | Apr 23 – May 7 | — | Jun 23 – Jul 14 |
| Okra | Mar 26 – Apr 9 | May 28 – Jun 11 | May 28 – Jun 11 | — |
| Basil | Mar 26 – Apr 9 | May 14 – May 28 | — | — |
| Peas | — | — | Mar 26 – Apr 16 | Jul 7 – Jul 28 |
| Spinach | — | — | Mar 26 – Apr 16 | Aug 4 – Aug 25 |
| Radishes | — | — | Apr 2 – May 14 | Aug 18 – Sep 8 |
| Cucumbers | Apr 9 – Apr 16 | May 21 – May 28 | May 14 – May 28 | Jul 14 – Jul 28 |
| Zucchini & Summer Squash | Apr 9 – Apr 16 | — | May 14 – May 28 | Jul 21 – Aug 4 |
| Winter Squash & Pumpkins | Apr 9 – Apr 16 | — | May 14 – May 28 | — |
| Melons & Watermelon | Apr 9 – Apr 16 | May 21 – Jun 4 | — | — |
| Carrots | — | — | Apr 16 – May 14 | Jul 7 – Jul 21 |
| Beets | — | — | Apr 16 – May 14 | Jul 21 – Aug 4 |
| Potatoes | — | — | Apr 16 – May 7 | — |
| Swiss Chard | — | — | Apr 23 – May 21 | Jul 21 – Aug 4 |
| Cilantro | — | — | Apr 23 – May 14 | Aug 4 – Aug 25 |
| Green Beans | — | — | May 14 – Jun 4 | Jul 14 – Jul 28 |
| Sweet Corn | — | — | May 14 – May 28 | — |
| Sweet Potatoes | — | May 21 – Jun 11 | — | — |
| Garlic | — | — | — | Sep 15 – Oct 20 |
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 Salem 5ne, SD weather station, 24 km away (elevation 1,594 ft (486 m)).
Frost dates near Humboldt
- Hartford Apr 26 · Oct 13
- Montrose May 7 · Sep 29
- Monroe Apr 30 · Oct 7
- Canistota Apr 30 · Oct 7
- Lyons Apr 26 · Oct 13
- Crooks Apr 26 · Oct 13
- Colton May 3 · Oct 4
- Chancellor Apr 26 · Oct 13
- Parker Apr 30 · Oct 7
- Tea Apr 26 · Oct 13
Frequently asked questions
When is the last frost in Humboldt, SD?
The median last spring frost in Humboldt, SD is May 7. There is still about a 10% chance of frost after May 19, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Humboldt, SD?
The median first fall frost is September 29, with about a 10% chance of frost before September 17.
How long is the growing season in Humboldt, SD?
About 145 days between the median last spring frost and first fall frost.
What planting zone is Humboldt, SD?
Humboldt, SD is in USDA hardiness zone 4b.