Frost dates for 63302 — Saint Charles, MO
Last spring frostApr 8median date
First fall frostOct 29median date
Growing season204 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 23 and April 24, a 32-day window. The first fall frost falls between October 16 and November 12.
- The median last frost is 4 days earlier than the Missouri median of Apr 12.
- Its 204-day growing season is longer than 77% of the 938 Missouri places with a regular frost season (state median 195 days).
- The last frost is 8 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 105 nights a year at or below 32°F.
- Compared with O Fallon, MO, 22 km away, the last frost here is 2 days earlier than there and the growing season is 5 days longer.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 23 |
| 50% (median) | April 8 |
| 10% (safe for tender plants) | April 24 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 16 |
| 50% (median) | October 29 |
| 90% (late) | November 12 |
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 63302 — Saint Charles, MO — last frost Apr 8, first frost Oct 29, zone 7a. whenisthelastfrost.com
Crop
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Start indoors: Jan 14 to Jan 28Transplant outside: Mar 11 to Mar 25
Start indoors: Jan 28 to Feb 11Transplant outside: Apr 22 to May 6
Start indoors: Jan 28 to Feb 11Transplant outside: Apr 22 to May 6
Start indoors: Feb 11 to Feb 25Transplant outside: Apr 15 to Apr 29
Start indoors: Feb 11 to Feb 25Transplant outside: Mar 18 to Apr 1Sow outdoors: Mar 11 to Apr 15Plant for fall: Sep 3 to Oct 1
Start indoors: Feb 11 to Feb 25Transplant outside: Mar 11 to Mar 25Sow outdoors: Mar 11 to Mar 25Plant for fall: Aug 20 to Sep 10
Start indoors: Feb 11 to Feb 25Transplant outside: Mar 25 to Apr 8Plant for fall: Jul 23 to Aug 13
Start indoors: Feb 11 to Feb 25Transplant outside: Mar 18 to Apr 1Plant for fall: Jul 23 to Aug 13
Start indoors: Feb 11 to Feb 25Transplant outside: Mar 25 to Apr 8Plant for fall: Jul 23 to Aug 13
Start indoors: Feb 25 to Mar 11Transplant outside: Apr 29 to May 13Sow outdoors: Apr 29 to May 13
Start indoors: Feb 25 to Mar 11Transplant outside: Apr 15 to Apr 29
Sow outdoors: Feb 25 to Mar 18Plant for fall: Aug 6 to Aug 27
Sow outdoors: Feb 25 to Mar 18Plant for fall: Sep 3 to Sep 24
Sow outdoors: Mar 4 to Apr 15Plant for fall: Sep 17 to Oct 8
Start indoors: Mar 11 to Mar 18Transplant outside: Apr 22 to Apr 29Sow outdoors: Apr 15 to Apr 29Plant for fall: Aug 13 to Aug 27
Start indoors: Mar 11 to Mar 18Sow outdoors: Apr 15 to Apr 29Plant for fall: Aug 20 to Sep 3
Start indoors: Mar 11 to Mar 18Sow outdoors: Apr 15 to Apr 29
Start indoors: Mar 11 to Mar 18Transplant outside: Apr 22 to May 6
Sow outdoors: Mar 18 to Apr 15Plant for fall: Aug 6 to Aug 20
Sow outdoors: Mar 18 to Apr 15Plant for fall: Aug 20 to Sep 3
Sow outdoors: Mar 18 to Apr 8
Sow outdoors: Mar 25 to Apr 22Plant for fall: Aug 20 to Sep 3
Sow outdoors: Mar 25 to Apr 15Plant for fall: Sep 3 to Sep 24
Sow outdoors: Apr 15 to May 6Plant for fall: Aug 13 to Aug 27
Sow outdoors: Apr 15 to Apr 29
Transplant outside: Apr 22 to May 13
Plant for fall: Oct 15 to Nov 19
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 14 – Jan 28 | Mar 11 – Mar 25 | — | — |
| Peppers | Jan 28 – Feb 11 | Apr 22 – May 6 | — | — |
| Eggplant | Jan 28 – Feb 11 | Apr 22 – May 6 | — | — |
| Tomatoes | Feb 11 – Feb 25 | Apr 15 – Apr 29 | — | — |
| Lettuce | Feb 11 – Feb 25 | Mar 18 – Apr 1 | Mar 11 – Apr 15 | Sep 3 – Oct 1 |
| Kale | Feb 11 – Feb 25 | Mar 11 – Mar 25 | Mar 11 – Mar 25 | Aug 20 – Sep 10 |
| Broccoli | Feb 11 – Feb 25 | Mar 25 – Apr 8 | — | Jul 23 – Aug 13 |
| Cabbage | Feb 11 – Feb 25 | Mar 18 – Apr 1 | — | Jul 23 – Aug 13 |
| Cauliflower | Feb 11 – Feb 25 | Mar 25 – Apr 8 | — | Jul 23 – Aug 13 |
| Okra | Feb 25 – Mar 11 | Apr 29 – May 13 | Apr 29 – May 13 | — |
| Basil | Feb 25 – Mar 11 | Apr 15 – Apr 29 | — | — |
| Peas | — | — | Feb 25 – Mar 18 | Aug 6 – Aug 27 |
| Spinach | — | — | Feb 25 – Mar 18 | Sep 3 – Sep 24 |
| Radishes | — | — | Mar 4 – Apr 15 | Sep 17 – Oct 8 |
| Cucumbers | Mar 11 – Mar 18 | Apr 22 – Apr 29 | Apr 15 – Apr 29 | Aug 13 – Aug 27 |
| Zucchini & Summer Squash | Mar 11 – Mar 18 | — | Apr 15 – Apr 29 | Aug 20 – Sep 3 |
| Winter Squash & Pumpkins | Mar 11 – Mar 18 | — | Apr 15 – Apr 29 | — |
| Melons & Watermelon | Mar 11 – Mar 18 | Apr 22 – May 6 | — | — |
| Carrots | — | — | Mar 18 – Apr 15 | Aug 6 – Aug 20 |
| Beets | — | — | Mar 18 – Apr 15 | Aug 20 – Sep 3 |
| Potatoes | — | — | Mar 18 – Apr 8 | — |
| Swiss Chard | — | — | Mar 25 – Apr 22 | Aug 20 – Sep 3 |
| Cilantro | — | — | Mar 25 – Apr 15 | Sep 3 – Sep 24 |
| Green Beans | — | — | Apr 15 – May 6 | Aug 13 – Aug 27 |
| Sweet Corn | — | — | Apr 15 – Apr 29 | — |
| Sweet Potatoes | — | Apr 22 – May 13 | — | — |
| Garlic | — | — | — | Oct 15 – Nov 19 |
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 Charles Elm Pt, MO weather station, 4 km away (elevation 472 ft (144 m)).
ZIP codes in Saint Charles: 63301 63302 63303 63304
Frost dates near Saint Charles
- Earth City Apr 8 · Oct 29
- Flinthill Apr 9 · Oct 26
- Bridgeton Apr 2 · Nov 4
- Maryland Heights Apr 2 · Nov 4
- Hazelwood Apr 2 · Nov 4
- Saint Ann Apr 2 · Nov 4
- Saint Peters Apr 9 · Oct 26
- Florissant 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 8. There is still about a 10% chance of frost after April 24, 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 29, with about a 10% chance of frost before October 16.
How long is the growing season in Saint Charles, MO?
About 204 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.