USDA Hardiness Zone 7a
Frost Dates for 62951 — Johnston City, Illinois
Averages from Carbondale Sewage Plt, Il US, the nearest reporting station, 14.5 miles away.
Plant tender crops after April 9, and expect the first autumn freeze around October 22. That leaves about 195 frost-free days.
- Last spring frost
- April 9
- First fall frost
- October 22
- Growing season
- 195 days
- Hardiness zone
- 7a
50% probability
50% probability
frost-free
0 to 5°F annual low
Planting calendar for 62951
| 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 July 30 | Sow the autumn crop of carrots, beets and brassicas They need about twelve weeks to size up before growth stops. |
| by October 8 | Harvest tender crops, or be ready to cover them A first freeze two weeks early is well within normal variation. |
| October 22 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 Johnston City, Illinois are past their last freeze. Harvest before October 22, which leaves roughly 195 frost-free days.
ZIP 62951 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.