Frost dates for 63121 — Saint Louis, MO
How Saint Louis compares
- In 8 years out of 10, the last spring frost in Saint Louis falls between March 17 and April 17, a 31-day window. The first fall frost falls between October 23 and November 18.
- The median last frost is 10 days earlier than the Missouri median of Apr 12.
- Its 216-day growing season is longer than 94% of the 938 Missouri places with a regular frost season (state median 195 days).
- The last frost is 14 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 85 nights a year at or below 32°F.
- Saint Louis shares its weather station with Florissant, MO, 7 km away, so the two have the same frost dates.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | March 17 |
| 50% (median) | April 2 |
| 10% (safe for tender plants) | April 17 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 23 |
| 50% (median) | November 4 |
| 90% (late) | November 18 |
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 Louis, MO
Frost dates for 63121 — Saint Louis, MO — last frost Apr 2, first frost Nov 4, zone 7a. whenisthelastfrost.com
When to plant vegetables in Saint Louis, MO
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 8 – Jan 22 | Mar 5 – Mar 19 | — | — |
| Peppers | Jan 22 – Feb 5 | Apr 16 – Apr 30 | — | — |
| Eggplant | Jan 22 – Feb 5 | Apr 16 – Apr 30 | — | — |
| Tomatoes | Feb 5 – Feb 19 | Apr 9 – Apr 23 | — | — |
| Lettuce | Feb 5 – Feb 19 | Mar 12 – Mar 26 | Mar 5 – Apr 9 | Sep 9 – Oct 7 |
| Kale | Feb 5 – Feb 19 | Mar 5 – Mar 19 | Mar 5 – Mar 19 | Aug 26 – Sep 16 |
| Broccoli | Feb 5 – Feb 19 | Mar 19 – Apr 2 | — | Jul 29 – Aug 19 |
| Cabbage | Feb 5 – Feb 19 | Mar 12 – Mar 26 | — | Jul 29 – Aug 19 |
| Cauliflower | Feb 5 – Feb 19 | Mar 19 – Apr 2 | — | Jul 29 – Aug 19 |
| Okra | Feb 19 – Mar 5 | Apr 23 – May 7 | Apr 23 – May 7 | — |
| Basil | Feb 19 – Mar 5 | Apr 9 – Apr 23 | — | — |
| Peas | — | — | Feb 19 – Mar 12 | Aug 12 – Sep 2 |
| Spinach | — | — | Feb 19 – Mar 12 | Sep 9 – Sep 30 |
| Radishes | — | — | Feb 26 – Apr 9 | Sep 23 – Oct 14 |
| Cucumbers | Mar 5 – Mar 12 | Apr 16 – Apr 23 | Apr 9 – Apr 23 | Aug 19 – Sep 2 |
| Zucchini & Summer Squash | Mar 5 – Mar 12 | — | Apr 9 – Apr 23 | Aug 26 – Sep 9 |
| Winter Squash & Pumpkins | Mar 5 – Mar 12 | — | Apr 9 – Apr 23 | — |
| Melons & Watermelon | Mar 5 – Mar 12 | Apr 16 – Apr 30 | — | — |
| Carrots | — | — | Mar 12 – Apr 9 | Aug 12 – Aug 26 |
| Beets | — | — | Mar 12 – Apr 9 | Aug 26 – Sep 9 |
| Potatoes | — | — | Mar 12 – Apr 2 | — |
| Swiss Chard | — | — | Mar 19 – Apr 16 | Aug 26 – Sep 9 |
| Cilantro | — | — | Mar 19 – Apr 9 | Sep 9 – Sep 30 |
| Green Beans | — | — | Apr 9 – Apr 30 | Aug 19 – Sep 2 |
| Sweet Corn | — | — | Apr 9 – Apr 23 | — |
| Sweet Potatoes | — | Apr 16 – May 7 | — | — |
| Garlic | — | — | — | Oct 21 – Nov 25 |
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 Louis Lambert Intl Ap, MO weather station, 8 km away (elevation 531 ft (162 m)).
ZIP codes in Saint Louis: 63101 63102 63103 63104 63105 63106 63107 63108 63109 63110 63111 63112 63113 63114 63115 63116 63117 63118 63119 63120 63121 63122 63123 63124 63125 63126 63127 63128 63129 63130 63131 63132 63133 63134 63135 63136 63137 63138 63139 63140 63141 63143 63144 63145 63146 63147 63150 63151 63155 63156 63157 63158 63160 63163 63164 63166 63167 63169 63171 63177 …
Frost dates near Saint Louis
- Saint Ann Apr 2 · Nov 4
- Florissant Apr 2 · Nov 4
- Hazelwood Apr 2 · Nov 4
- Bridgeton Apr 2 · Nov 4
- Maryland Heights Apr 2 · Nov 4
- Earth City Apr 8 · Oct 29
- Fenton Apr 4 · Oct 29
- West Alton Apr 4 · Nov 5
Frequently asked questions
When is the last frost in Saint Louis, MO?
The median last spring frost in Saint Louis, MO is April 2. There is still about a 10% chance of frost after April 17, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Saint Louis, MO?
The median first fall frost is November 4, with about a 10% chance of frost before October 23.
How long is the growing season in Saint Louis, MO?
About 216 days between the median last spring frost and first fall frost.
What planting zone is Saint Louis, MO?
Saint Louis, MO is in USDA hardiness zone 7a.