Frost dates for Harrisburg, IL
When the last spring frost and first fall frost usually come, and when to plant, from 30 years of NOAA weather records.
Last spring frost
April 7
typical year
Safe to plant
April 25
frost is over in 9 of 10 years
First fall frost
October 26
typical year
Growing season
202 days
frost-free, typical year
Frost watch this week
Tonight's and the next six nights' lows from the National Weather Service forecast for the station's location. Frost: 32°F or colder. Possible frost: 33–36°F, mostly in low spots on clear, still nights.
When to plant
Counted from this page's frost dates. Warm-season crops wait for the safe-to-plant date.
| Crop | Start indoors | Plant outside | Fall planting |
|---|---|---|---|
| Cool-season crops | |||
| Peas | – | Mar 10 – 24 | – |
| Spinach | – | Feb 24 – Mar 17 | Aug 31 – Sep 14 |
| Lettuce | – | Mar 10 – 31 | Aug 31 – Sep 14 |
| Radishes | – | Mar 10 – Apr 21 | Sep 14 – 28 |
| Onions | – | Mar 10 – 24 | – |
| Potatoes | – | Mar 17 – 31 | – |
| Carrots | – | Mar 17 – Apr 7 | Aug 3 – 17 |
| Beets | – | Mar 10 – 24 | Aug 17 – 31 |
| Kale | Jan 27 – Feb 10 | Mar 10 – 24 | Aug 17 – 31 |
| Broccoli | Jan 27 – Feb 10 | Mar 24 – Apr 7 | Aug 17 – 31 |
| Cabbage | Jan 13 – 27 | Mar 10 – 24 | Aug 17 – 31 |
| Garlic | – | – | Sep 14 – Oct 5 |
| Warm-season crops | |||
| Tomatoes | Feb 28 – Mar 14 | Apr 25 – May 9 | – |
| Peppers | Feb 21 – Mar 7 | May 2 – 16 | – |
| Cucumbers | – | Apr 25 – May 16 | – |
| Zucchini | – | Apr 25 – May 23 | – |
| Pumpkins | – | Apr 25 – May 16 | – |
| Green beans | – | Apr 25 – Aug 17 | – |
| Sweet corn | – | Apr 25 – May 23 | – |
| Basil | Mar 21 – Apr 4 | May 2 – 9 | – |
Onions: from sets. Green beans: until 10 weeks before the first fall frost. Garlic: harvest next summer.
The year at a glance
Start indoors Plant outside Fall planting
The chance of frost, by date
| 1 year in 10 | Half of years | 9 years in 10 | |
|---|---|---|---|
| Spring frost after | April 25 | April 7 | March 21 |
| Fall frost before | October 10 | October 26 | November 8 |
Frost here means 32°F or colder. Read across: in 1 year in 10, spring frost carries on past the first date, which is why that date is the safe-to-plant date.
Hard freeze (28°F)
A hard freeze kills most garden plants, even hardy ones. The last one in spring usually comes around March 26 (April 12 in a late year), and the first one in fall around November 6.
Towns that use these dates
This is the nearest NOAA station with frost records for 7 towns.
Harrisburg, Eldorado, Carrier Mills, Galatia, Equality, Raleigh, Muddy
Where these dates come from
NOAA weather station HARRISBURG, IL US (USC00113879), 1991–2020 climate normals. It's the nearest station for 10 zip codes, all within 15 miles:
62917, 62930, 62934, 62935, 62946, 62954, 62965, 62974, 62977, 62987
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.