Saint Olaf, IA frost dates
Last spring frostMay 8median date
First fall frostOct 1median date
Growing season146 daysfrost-free
Hardiness zone5aZone 5a
How Saint Olaf compares
- In 8 years out of 10, the last spring frost in Saint Olaf falls between April 24 and May 22, a 28-day window. The first fall frost falls between September 18 and October 14.
- The median last frost is 10 days later than the Iowa median of Apr 28.
- Its 146-day growing season is among the shortest of the 934 Iowa places with a regular frost season.
- The last frost is 5 days later than the zone 5a median of May 3. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5a chart.
- The weather station records an average of 164 nights a year at or below 32°F.
- Compared with Dubuque, IA, 73 km away, the last frost here is 19 days later than there and the growing season is 39 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 24 |
| 50% (median) | May 8 |
| 10% (safe for tender plants) | May 22 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 18 |
| 50% (median) | October 1 |
| 90% (late) | October 14 |
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 Saint Olaf, IA
Saint Olaf, IA frost dates — last frost May 8, first frost Oct 1, zone 5a. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Feb 13 to Feb 27Transplant outside: Apr 10 to Apr 24
Start indoors: Feb 27 to Mar 13Transplant outside: May 22 to Jun 5
Start indoors: Feb 27 to Mar 13Transplant outside: May 22 to Jun 5
Start indoors: Mar 13 to Mar 27Transplant outside: May 15 to May 29
Start indoors: Mar 13 to Mar 27Transplant outside: Apr 17 to May 1Sow outdoors: Apr 10 to May 15Plant for fall: Aug 6 to Sep 3
Start indoors: Mar 13 to Mar 27Transplant outside: Apr 10 to Apr 24Sow outdoors: Apr 10 to Apr 24Plant for fall: Jul 23 to Aug 13
Start indoors: Mar 13 to Mar 27Transplant outside: Apr 24 to May 8Plant for fall: Jun 25 to Jul 16
Start indoors: Mar 13 to Mar 27Transplant outside: Apr 17 to May 1Plant for fall: Jun 25 to Jul 16
Start indoors: Mar 13 to Mar 27Transplant outside: Apr 24 to May 8Plant for fall: Jun 25 to Jul 16
Start indoors: Mar 27 to Apr 10Transplant outside: May 29 to Jun 12Sow outdoors: May 29 to Jun 12
Start indoors: Mar 27 to Apr 10Transplant outside: May 15 to May 29
Sow outdoors: Mar 27 to Apr 17Plant for fall: Jul 9 to Jul 30
Sow outdoors: Mar 27 to Apr 17Plant for fall: Aug 6 to Aug 27
Sow outdoors: Apr 3 to May 15Plant for fall: Aug 20 to Sep 10
Start indoors: Apr 10 to Apr 17Transplant outside: May 22 to May 29Sow outdoors: May 15 to May 29Plant for fall: Jul 16 to Jul 30
Start indoors: Apr 10 to Apr 17Sow outdoors: May 15 to May 29Plant for fall: Jul 23 to Aug 6
Start indoors: Apr 10 to Apr 17Sow outdoors: May 15 to May 29
Start indoors: Apr 10 to Apr 17Transplant outside: May 22 to Jun 5
Sow outdoors: Apr 17 to May 15Plant for fall: Jul 9 to Jul 23
Sow outdoors: Apr 17 to May 15Plant for fall: Jul 23 to Aug 6
Sow outdoors: Apr 17 to May 8
Sow outdoors: Apr 24 to May 22Plant for fall: Jul 23 to Aug 6
Sow outdoors: Apr 24 to May 15Plant for fall: Aug 6 to Aug 27
Sow outdoors: May 15 to Jun 5Plant for fall: Jul 16 to Jul 30
Sow outdoors: May 15 to May 29
Transplant outside: May 22 to Jun 12
Plant for fall: Sep 17 to Oct 22
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Saint Olaf, IA
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 13 – Feb 27 | Apr 10 – Apr 24 | — | — |
| Peppers | Feb 27 – Mar 13 | May 22 – Jun 5 | — | — |
| Eggplant | Feb 27 – Mar 13 | May 22 – Jun 5 | — | — |
| Tomatoes | Mar 13 – Mar 27 | May 15 – May 29 | — | — |
| Lettuce | Mar 13 – Mar 27 | Apr 17 – May 1 | Apr 10 – May 15 | Aug 6 – Sep 3 |
| Kale | Mar 13 – Mar 27 | Apr 10 – Apr 24 | Apr 10 – Apr 24 | Jul 23 – Aug 13 |
| Broccoli | Mar 13 – Mar 27 | Apr 24 – May 8 | — | Jun 25 – Jul 16 |
| Cabbage | Mar 13 – Mar 27 | Apr 17 – May 1 | — | Jun 25 – Jul 16 |
| Cauliflower | Mar 13 – Mar 27 | Apr 24 – May 8 | — | Jun 25 – Jul 16 |
| Okra | Mar 27 – Apr 10 | May 29 – Jun 12 | May 29 – Jun 12 | — |
| Basil | Mar 27 – Apr 10 | May 15 – May 29 | — | — |
| Peas | — | — | Mar 27 – Apr 17 | Jul 9 – Jul 30 |
| Spinach | — | — | Mar 27 – Apr 17 | Aug 6 – Aug 27 |
| Radishes | — | — | Apr 3 – May 15 | Aug 20 – Sep 10 |
| Cucumbers | Apr 10 – Apr 17 | May 22 – May 29 | May 15 – May 29 | Jul 16 – Jul 30 |
| Zucchini & Summer Squash | Apr 10 – Apr 17 | — | May 15 – May 29 | Jul 23 – Aug 6 |
| Winter Squash & Pumpkins | Apr 10 – Apr 17 | — | May 15 – May 29 | — |
| Melons & Watermelon | Apr 10 – Apr 17 | May 22 – Jun 5 | — | — |
| Carrots | — | — | Apr 17 – May 15 | Jul 9 – Jul 23 |
| Beets | — | — | Apr 17 – May 15 | Jul 23 – Aug 6 |
| Potatoes | — | — | Apr 17 – May 8 | — |
| Swiss Chard | — | — | Apr 24 – May 22 | Jul 23 – Aug 6 |
| Cilantro | — | — | Apr 24 – May 15 | Aug 6 – Aug 27 |
| Green Beans | — | — | May 15 – Jun 5 | Jul 16 – Jul 30 |
| Sweet Corn | — | — | May 15 – May 29 | — |
| Sweet Potatoes | — | May 22 – Jun 12 | — | — |
| 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 Elkader 6 Ssw, IA weather station, 17 km away (elevation 787 ft (240 m)).
Frost dates near Saint Olaf
- Farmersburg Apr 28 · Oct 12
- Elkader May 8 · Oct 1
- Monona May 1 · Oct 3
- Garnavillo Apr 21 · Oct 18
- Luana May 1 · Oct 3
- Postville May 1 · Oct 3
- Elkport May 8 · Oct 1
- Mc Gregor Apr 28 · Oct 12
- Marquette Apr 28 · Oct 12
- Volga May 8 · Oct 1
Frequently asked questions
When is the last frost in Saint Olaf, IA?
The median last spring frost in Saint Olaf, IA is May 8. There is still about a 10% chance of frost after May 22, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Saint Olaf, IA?
The median first fall frost is October 1, with about a 10% chance of frost before September 18.
How long is the growing season in Saint Olaf, IA?
About 146 days between the median last spring frost and first fall frost.
What planting zone is Saint Olaf, IA?
Saint Olaf, IA is in USDA hardiness zone 5a.