Frost dates for 63303 — Saint Charles, MO
Last spring frostApr 9median date
First fall frostOct 26median date
Growing season200 daysfrost-free
Hardiness zone7aZone 7a
How Saint Charles compares
- In 8 years out of 10, the last spring frost in Saint Charles falls between March 27 and April 25, a 29-day window. The first fall frost falls between October 14 and November 7.
- The median last frost is 3 days earlier than the Missouri median of Apr 12.
- Its 200-day growing season is longer than 62% of the 938 Missouri places with a regular frost season (state median 195 days).
- The last frost is 7 days earlier than the zone 7a median of Apr 16. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 7a chart.
- The weather station records an average of 103 nights a year at or below 32°F.
- Compared with O Fallon, MO, 17 km away, the last frost here is 1 day earlier than there and the growing season is 1 day longer.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 27 |
| 50% (median) | April 9 |
| 10% (safe for tender plants) | April 25 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 14 |
| 50% (median) | October 26 |
| 90% (late) | November 7 |
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 Charles, MO
Frost dates for 63303 — Saint Charles, MO — last frost Apr 9, first frost Oct 26, zone 7a. whenisthelastfrost.com
Crop
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Start indoors: Jan 15 to Jan 29Transplant outside: Mar 12 to Mar 26
Start indoors: Jan 29 to Feb 12Transplant outside: Apr 23 to May 7
Start indoors: Jan 29 to Feb 12Transplant outside: Apr 23 to May 7
Start indoors: Feb 12 to Feb 26Transplant outside: Apr 16 to Apr 30
Start indoors: Feb 12 to Feb 26Transplant outside: Mar 19 to Apr 2Sow outdoors: Mar 12 to Apr 16Plant for fall: Aug 31 to Sep 28
Start indoors: Feb 12 to Feb 26Transplant outside: Mar 12 to Mar 26Sow outdoors: Mar 12 to Mar 26Plant for fall: Aug 17 to Sep 7
Start indoors: Feb 12 to Feb 26Transplant outside: Mar 26 to Apr 9Plant for fall: Jul 20 to Aug 10
Start indoors: Feb 12 to Feb 26Transplant outside: Mar 19 to Apr 2Plant for fall: Jul 20 to Aug 10
Start indoors: Feb 12 to Feb 26Transplant outside: Mar 26 to Apr 9Plant for fall: Jul 20 to Aug 10
Start indoors: Feb 26 to Mar 12Transplant outside: Apr 30 to May 14Sow outdoors: Apr 30 to May 14
Start indoors: Feb 26 to Mar 12Transplant outside: Apr 16 to Apr 30
Sow outdoors: Feb 26 to Mar 19Plant for fall: Aug 3 to Aug 24
Sow outdoors: Feb 26 to Mar 19Plant for fall: Aug 31 to Sep 21
Sow outdoors: Mar 5 to Apr 16Plant for fall: Sep 14 to Oct 5
Start indoors: Mar 12 to Mar 19Transplant outside: Apr 23 to Apr 30Sow outdoors: Apr 16 to Apr 30Plant for fall: Aug 10 to Aug 24
Start indoors: Mar 12 to Mar 19Sow outdoors: Apr 16 to Apr 30Plant for fall: Aug 17 to Aug 31
Start indoors: Mar 12 to Mar 19Sow outdoors: Apr 16 to Apr 30
Start indoors: Mar 12 to Mar 19Transplant outside: Apr 23 to May 7
Sow outdoors: Mar 19 to Apr 16Plant for fall: Aug 3 to Aug 17
Sow outdoors: Mar 19 to Apr 16Plant for fall: Aug 17 to Aug 31
Sow outdoors: Mar 19 to Apr 9
Sow outdoors: Mar 26 to Apr 23Plant for fall: Aug 17 to Aug 31
Sow outdoors: Mar 26 to Apr 16Plant for fall: Aug 31 to Sep 21
Sow outdoors: Apr 16 to May 7Plant for fall: Aug 10 to Aug 24
Sow outdoors: Apr 16 to Apr 30
Transplant outside: Apr 23 to May 14
Plant for fall: Oct 12 to Nov 16
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Saint Charles, MO
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 15 – Jan 29 | Mar 12 – Mar 26 | — | — |
| Peppers | Jan 29 – Feb 12 | Apr 23 – May 7 | — | — |
| Eggplant | Jan 29 – Feb 12 | Apr 23 – May 7 | — | — |
| Tomatoes | Feb 12 – Feb 26 | Apr 16 – Apr 30 | — | — |
| Lettuce | Feb 12 – Feb 26 | Mar 19 – Apr 2 | Mar 12 – Apr 16 | Aug 31 – Sep 28 |
| Kale | Feb 12 – Feb 26 | Mar 12 – Mar 26 | Mar 12 – Mar 26 | Aug 17 – Sep 7 |
| Broccoli | Feb 12 – Feb 26 | Mar 26 – Apr 9 | — | Jul 20 – Aug 10 |
| Cabbage | Feb 12 – Feb 26 | Mar 19 – Apr 2 | — | Jul 20 – Aug 10 |
| Cauliflower | Feb 12 – Feb 26 | Mar 26 – Apr 9 | — | Jul 20 – Aug 10 |
| Okra | Feb 26 – Mar 12 | Apr 30 – May 14 | Apr 30 – May 14 | — |
| Basil | Feb 26 – Mar 12 | Apr 16 – Apr 30 | — | — |
| Peas | — | — | Feb 26 – Mar 19 | Aug 3 – Aug 24 |
| Spinach | — | — | Feb 26 – Mar 19 | Aug 31 – Sep 21 |
| Radishes | — | — | Mar 5 – Apr 16 | Sep 14 – Oct 5 |
| Cucumbers | Mar 12 – Mar 19 | Apr 23 – Apr 30 | Apr 16 – Apr 30 | Aug 10 – Aug 24 |
| Zucchini & Summer Squash | Mar 12 – Mar 19 | — | Apr 16 – Apr 30 | Aug 17 – Aug 31 |
| Winter Squash & Pumpkins | Mar 12 – Mar 19 | — | Apr 16 – Apr 30 | — |
| Melons & Watermelon | Mar 12 – Mar 19 | Apr 23 – May 7 | — | — |
| Carrots | — | — | Mar 19 – Apr 16 | Aug 3 – Aug 17 |
| Beets | — | — | Mar 19 – Apr 16 | Aug 17 – Aug 31 |
| Potatoes | — | — | Mar 19 – Apr 9 | — |
| Swiss Chard | — | — | Mar 26 – Apr 23 | Aug 17 – Aug 31 |
| Cilantro | — | — | Mar 26 – Apr 16 | Aug 31 – Sep 21 |
| Green Beans | — | — | Apr 16 – May 7 | Aug 10 – Aug 24 |
| Sweet Corn | — | — | Apr 16 – Apr 30 | — |
| Sweet Potatoes | — | Apr 23 – May 14 | — | — |
| Garlic | — | — | — | Oct 12 – Nov 16 |
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 St Peters 2 Se, MO weather station, 4 km away (elevation 574 ft (175 m)).
ZIP codes in Saint Charles: 63301 63302 63303 63304
Frost dates near Saint Charles
- Flinthill Apr 9 · Oct 26
- Saint Peters Apr 9 · Oct 26
- Earth City Apr 8 · Oct 29
- Cottleville Apr 10 · Oct 26
- Maryland Heights Apr 2 · Nov 4
- Bridgeton Apr 2 · Nov 4
- Chesterfield Apr 4 · Oct 29
- Saint Ann Apr 2 · Nov 4
Frequently asked questions
When is the last frost in Saint Charles, MO?
The median last spring frost in Saint Charles, MO is April 9. 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 Charles, MO?
The median first fall frost is October 26, with about a 10% chance of frost before October 14.
How long is the growing season in Saint Charles, MO?
About 200 days between the median last spring frost and first fall frost.
What planting zone is Saint Charles, MO?
Saint Charles, MO is in USDA hardiness zone 7a.