USDA Hardiness Zone 7a
Frost Dates for 63303 — Saint Charles, Missouri
Averages from St Peters 2 Se, Mo US, the nearest reporting station, 2.7 miles away.
Plant tender crops after April 9, and expect the first autumn freeze around October 26. That leaves about 198 frost-free days.
- Last spring frost
- April 9
- First fall frost
- October 26
- Growing season
- 198 days
- Hardiness zone
- 7a
50% probability
50% probability
frost-free
0 to 5°F annual low
Planting calendar for 63303
| When | What to do |
|---|---|
| January 29 – February 12 | Start peppers and aubergines indoors They need eight to ten weeks under lights before they can go out. |
| February 12 – February 26 | Start tomatoes indoors Six to eight weeks gives a transplant big enough to set fruit early. |
| March 12 – March 26 | Sow peas, spinach, lettuce, radish outdoors These tolerate light frost and prefer to germinate in cool soil. |
| April 9 onward | Transplant tomatoes, peppers, basil, squash, cucumbers The average last freeze has passed — still watch the actual forecast. |
| by August 3 | Sow the autumn crop of carrots, beets and brassicas They need about twelve weeks to size up before growth stops. |
| by October 12 | Harvest tender crops, or be ready to cover them A first freeze two weeks early is well within normal variation. |
| October 26 onward | Plant garlic, mulch beds, lift tender bulbs Garlic wants a cold spell; bare soil loses structure over winter. |
What these dates mean
Wait until after April 9 to put tender plants — tomatoes, peppers, basil, squash — in the ground. That is the date by which half of years in Saint Charles, Missouri are past their last freeze. Harvest before October 26, which leaves roughly 198 frost-free days.
ZIP 63303 sits in USDA hardiness zone 7a, meaning the average coldest night of the year falls between 0 to 5°F. Zone decides what survives the winter; frost dates decide when to plant each spring. They are different questions, and a plant can pass one and fail the other.
These are thirty-year NOAA averages for 1991–2020, not a forecast. Any individual year can frost two to three weeks either side of these dates, so check the actual forecast before planting out.