Saint Peter, IL frost dates
Last spring frostApr 3median date
First fall frostOct 24median date
Growing season204 daysfrost-free
Hardiness zone6bZone 6b
How Saint Peter compares
- In 8 years out of 10, the last spring frost in Saint Peter falls between March 19 and April 25, a 37-day window. The first fall frost falls between October 9 and November 8.
- The median last frost is 14 days earlier than the Illinois median of Apr 17.
- Its 204-day growing season is longer than 89% of the 1,287 Illinois places with a regular frost season (state median 187 days).
- The last frost is 19 days earlier than the zone 6b median of Apr 22. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6b chart.
- The weather station records an average of 105 nights a year at or below 32°F.
- Compared with Decatur, IL, 109 km away, the last frost here is 11 days earlier than there and the growing season is 11 days longer.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 19 |
| 50% (median) | April 3 |
| 10% (safe for tender plants) | April 25 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 9 |
| 50% (median) | October 24 |
| 90% (late) | November 8 |
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 Peter, IL
Saint Peter, IL frost dates — last frost Apr 3, first frost Oct 24, zone 6b. whenisthelastfrost.com
Crop
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Start indoors: Jan 9 to Jan 23Transplant outside: Mar 6 to Mar 20
Start indoors: Jan 23 to Feb 6Transplant outside: Apr 17 to May 1
Start indoors: Jan 23 to Feb 6Transplant outside: Apr 17 to May 1
Start indoors: Feb 6 to Feb 20Transplant outside: Apr 10 to Apr 24
Start indoors: Feb 6 to Feb 20Transplant outside: Mar 13 to Mar 27Sow outdoors: Mar 6 to Apr 10Plant for fall: Aug 29 to Sep 26
Start indoors: Feb 6 to Feb 20Transplant outside: Mar 6 to Mar 20Sow outdoors: Mar 6 to Mar 20Plant for fall: Aug 15 to Sep 5
Start indoors: Feb 6 to Feb 20Transplant outside: Mar 20 to Apr 3Plant for fall: Jul 18 to Aug 8
Start indoors: Feb 6 to Feb 20Transplant outside: Mar 13 to Mar 27Plant for fall: Jul 18 to Aug 8
Start indoors: Feb 6 to Feb 20Transplant outside: Mar 20 to Apr 3Plant for fall: Jul 18 to Aug 8
Start indoors: Feb 20 to Mar 6Transplant outside: Apr 24 to May 8Sow outdoors: Apr 24 to May 8
Start indoors: Feb 20 to Mar 6Transplant outside: Apr 10 to Apr 24
Sow outdoors: Feb 20 to Mar 13Plant for fall: Aug 1 to Aug 22
Sow outdoors: Feb 20 to Mar 13Plant for fall: Aug 29 to Sep 19
Sow outdoors: Feb 27 to Apr 10Plant for fall: Sep 12 to Oct 3
Start indoors: Mar 6 to Mar 13Transplant outside: Apr 17 to Apr 24Sow outdoors: Apr 10 to Apr 24Plant for fall: Aug 8 to Aug 22
Start indoors: Mar 6 to Mar 13Sow outdoors: Apr 10 to Apr 24Plant for fall: Aug 15 to Aug 29
Start indoors: Mar 6 to Mar 13Sow outdoors: Apr 10 to Apr 24
Start indoors: Mar 6 to Mar 13Transplant outside: Apr 17 to May 1
Sow outdoors: Mar 13 to Apr 10Plant for fall: Aug 1 to Aug 15
Sow outdoors: Mar 13 to Apr 10Plant for fall: Aug 15 to Aug 29
Sow outdoors: Mar 13 to Apr 3
Sow outdoors: Mar 20 to Apr 17Plant for fall: Aug 15 to Aug 29
Sow outdoors: Mar 20 to Apr 10Plant for fall: Aug 29 to Sep 19
Sow outdoors: Apr 10 to May 1Plant for fall: Aug 8 to Aug 22
Sow outdoors: Apr 10 to Apr 24
Transplant outside: Apr 17 to May 8
Plant for fall: Oct 10 to Nov 14
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Saint Peter, IL
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 9 – Jan 23 | Mar 6 – Mar 20 | — | — |
| Peppers | Jan 23 – Feb 6 | Apr 17 – May 1 | — | — |
| Eggplant | Jan 23 – Feb 6 | Apr 17 – May 1 | — | — |
| Tomatoes | Feb 6 – Feb 20 | Apr 10 – Apr 24 | — | — |
| Lettuce | Feb 6 – Feb 20 | Mar 13 – Mar 27 | Mar 6 – Apr 10 | Aug 29 – Sep 26 |
| Kale | Feb 6 – Feb 20 | Mar 6 – Mar 20 | Mar 6 – Mar 20 | Aug 15 – Sep 5 |
| Broccoli | Feb 6 – Feb 20 | Mar 20 – Apr 3 | — | Jul 18 – Aug 8 |
| Cabbage | Feb 6 – Feb 20 | Mar 13 – Mar 27 | — | Jul 18 – Aug 8 |
| Cauliflower | Feb 6 – Feb 20 | Mar 20 – Apr 3 | — | Jul 18 – Aug 8 |
| Okra | Feb 20 – Mar 6 | Apr 24 – May 8 | Apr 24 – May 8 | — |
| Basil | Feb 20 – Mar 6 | Apr 10 – Apr 24 | — | — |
| Peas | — | — | Feb 20 – Mar 13 | Aug 1 – Aug 22 |
| Spinach | — | — | Feb 20 – Mar 13 | Aug 29 – Sep 19 |
| Radishes | — | — | Feb 27 – Apr 10 | Sep 12 – Oct 3 |
| Cucumbers | Mar 6 – Mar 13 | Apr 17 – Apr 24 | Apr 10 – Apr 24 | Aug 8 – Aug 22 |
| Zucchini & Summer Squash | Mar 6 – Mar 13 | — | Apr 10 – Apr 24 | Aug 15 – Aug 29 |
| Winter Squash & Pumpkins | Mar 6 – Mar 13 | — | Apr 10 – Apr 24 | — |
| Melons & Watermelon | Mar 6 – Mar 13 | Apr 17 – May 1 | — | — |
| Carrots | — | — | Mar 13 – Apr 10 | Aug 1 – Aug 15 |
| Beets | — | — | Mar 13 – Apr 10 | Aug 15 – Aug 29 |
| Potatoes | — | — | Mar 13 – Apr 3 | — |
| Swiss Chard | — | — | Mar 20 – Apr 17 | Aug 15 – Aug 29 |
| Cilantro | — | — | Mar 20 – Apr 10 | Aug 29 – Sep 19 |
| Green Beans | — | — | Apr 10 – May 1 | Aug 8 – Aug 22 |
| Sweet Corn | — | — | Apr 10 – Apr 24 | — |
| Sweet Potatoes | — | Apr 17 – May 8 | — | — |
| Garlic | — | — | — | Oct 10 – Nov 14 |
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 Brownstown 4 Sw, IL weather station, 13 km away (elevation 531 ft (162 m)).
Frost dates near Saint Peter
- Farina Apr 3 · Oct 24
- Kinmundy Apr 9 · Oct 26
- Brownstown Apr 3 · Oct 24
- Edgewood Apr 10 · Oct 23
- Alma Apr 9 · Oct 26
- Saint Elmo Apr 3 · Oct 24
- Shobonier Apr 10 · Oct 24
- Vernon Apr 10 · Oct 24
- Mason Apr 13 · Oct 24
- Vandalia Apr 10 · Oct 24
Frequently asked questions
When is the last frost in Saint Peter, IL?
The median last spring frost in Saint Peter, IL is April 3. There is still about a 10% chance of frost after April 25, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Saint Peter, IL?
The median first fall frost is October 24, with about a 10% chance of frost before October 9.
How long is the growing season in Saint Peter, IL?
About 204 days between the median last spring frost and first fall frost.
What planting zone is Saint Peter, IL?
Saint Peter, IL is in USDA hardiness zone 6b.