Hanover, IL frost dates
Last spring frostMay 1median date
First fall frostOct 9median date
Growing season161 daysfrost-free
Hardiness zone5aZone 5a
How Hanover compares
- In 8 years out of 10, the last spring frost in Hanover falls between April 17 and May 17, a 30-day window. The first fall frost falls between September 25 and October 23.
- The median last frost is 14 days later than the Illinois median of Apr 17.
- Its 161-day growing season is among the shortest of the 1,287 Illinois places with a regular frost season.
- The last frost is typical for zone 5a, where the median is May 3.
- The weather station records an average of 156 nights a year at or below 32°F.
- Compared with Dubuque, IA, 42 km away, the last frost here is 12 days later than there and the growing season is 24 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 17 |
| 50% (median) | May 1 |
| 10% (safe for tender plants) | May 17 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 25 |
| 50% (median) | October 9 |
| 90% (late) | October 23 |
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 Hanover, IL
Hanover, IL frost dates — last frost May 1, first frost Oct 9, zone 5a. whenisthelastfrost.com
Crop
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Start indoors: Feb 6 to Feb 20Transplant outside: Apr 3 to Apr 17
Start indoors: Feb 20 to Mar 6Transplant outside: May 15 to May 29
Start indoors: Feb 20 to Mar 6Transplant outside: May 15 to May 29
Start indoors: Mar 6 to Mar 20Transplant outside: May 8 to May 22
Start indoors: Mar 6 to Mar 20Transplant outside: Apr 10 to Apr 24Sow outdoors: Apr 3 to May 8Plant for fall: Aug 14 to Sep 11
Start indoors: Mar 6 to Mar 20Transplant outside: Apr 3 to Apr 17Sow outdoors: Apr 3 to Apr 17Plant for fall: Jul 31 to Aug 21
Start indoors: Mar 6 to Mar 20Transplant outside: Apr 17 to May 1Plant for fall: Jul 3 to Jul 24
Start indoors: Mar 6 to Mar 20Transplant outside: Apr 10 to Apr 24Plant for fall: Jul 3 to Jul 24
Start indoors: Mar 6 to Mar 20Transplant outside: Apr 17 to May 1Plant for fall: Jul 3 to Jul 24
Start indoors: Mar 20 to Apr 3Transplant outside: May 22 to Jun 5Sow outdoors: May 22 to Jun 5
Start indoors: Mar 20 to Apr 3Transplant outside: May 8 to May 22
Sow outdoors: Mar 20 to Apr 10Plant for fall: Jul 17 to Aug 7
Sow outdoors: Mar 20 to Apr 10Plant for fall: Aug 14 to Sep 4
Sow outdoors: Mar 27 to May 8Plant for fall: Aug 28 to Sep 18
Start indoors: Apr 3 to Apr 10Transplant outside: May 15 to May 22Sow outdoors: May 8 to May 22Plant for fall: Jul 24 to Aug 7
Start indoors: Apr 3 to Apr 10Sow outdoors: May 8 to May 22Plant for fall: Jul 31 to Aug 14
Start indoors: Apr 3 to Apr 10Sow outdoors: May 8 to May 22
Start indoors: Apr 3 to Apr 10Transplant outside: May 15 to May 29
Sow outdoors: Apr 10 to May 8Plant for fall: Jul 17 to Jul 31
Sow outdoors: Apr 10 to May 8Plant for fall: Jul 31 to Aug 14
Sow outdoors: Apr 10 to May 1
Sow outdoors: Apr 17 to May 15Plant for fall: Jul 31 to Aug 14
Sow outdoors: Apr 17 to May 8Plant for fall: Aug 14 to Sep 4
Sow outdoors: May 8 to May 29Plant for fall: Jul 24 to Aug 7
Sow outdoors: May 8 to May 22
Transplant outside: May 15 to Jun 5
Plant for fall: Sep 25 to Oct 30
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Hanover, IL
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 6 – Feb 20 | Apr 3 – Apr 17 | — | — |
| Peppers | Feb 20 – Mar 6 | May 15 – May 29 | — | — |
| Eggplant | Feb 20 – Mar 6 | May 15 – May 29 | — | — |
| Tomatoes | Mar 6 – Mar 20 | May 8 – May 22 | — | — |
| Lettuce | Mar 6 – Mar 20 | Apr 10 – Apr 24 | Apr 3 – May 8 | Aug 14 – Sep 11 |
| Kale | Mar 6 – Mar 20 | Apr 3 – Apr 17 | Apr 3 – Apr 17 | Jul 31 – Aug 21 |
| Broccoli | Mar 6 – Mar 20 | Apr 17 – May 1 | — | Jul 3 – Jul 24 |
| Cabbage | Mar 6 – Mar 20 | Apr 10 – Apr 24 | — | Jul 3 – Jul 24 |
| Cauliflower | Mar 6 – Mar 20 | Apr 17 – May 1 | — | Jul 3 – Jul 24 |
| Okra | Mar 20 – Apr 3 | May 22 – Jun 5 | May 22 – Jun 5 | — |
| Basil | Mar 20 – Apr 3 | May 8 – May 22 | — | — |
| Peas | — | — | Mar 20 – Apr 10 | Jul 17 – Aug 7 |
| Spinach | — | — | Mar 20 – Apr 10 | Aug 14 – Sep 4 |
| Radishes | — | — | Mar 27 – May 8 | Aug 28 – Sep 18 |
| Cucumbers | Apr 3 – Apr 10 | May 15 – May 22 | May 8 – May 22 | Jul 24 – Aug 7 |
| Zucchini & Summer Squash | Apr 3 – Apr 10 | — | May 8 – May 22 | Jul 31 – Aug 14 |
| Winter Squash & Pumpkins | Apr 3 – Apr 10 | — | May 8 – May 22 | — |
| Melons & Watermelon | Apr 3 – Apr 10 | May 15 – May 29 | — | — |
| Carrots | — | — | Apr 10 – May 8 | Jul 17 – Jul 31 |
| Beets | — | — | Apr 10 – May 8 | Jul 31 – Aug 14 |
| Potatoes | — | — | Apr 10 – May 1 | — |
| Swiss Chard | — | — | Apr 17 – May 15 | Jul 31 – Aug 14 |
| Cilantro | — | — | Apr 17 – May 8 | Aug 14 – Sep 4 |
| Green Beans | — | — | May 8 – May 29 | Jul 24 – Aug 7 |
| Sweet Corn | — | — | May 8 – May 22 | — |
| Sweet Potatoes | — | May 15 – Jun 5 | — | — |
| Garlic | — | — | — | Sep 25 – Oct 30 |
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 Elizabeth, IL weather station, 8 km away (elevation 676 ft (206 m)).
Frost dates near Hanover
- Elizabeth May 1 · Oct 9
- Galena Apr 26 · Oct 15
- Savanna May 2 · Oct 7
- Scales Mound Apr 26 · Oct 15
- Stockton Apr 27 · Oct 9
- Apple River Apr 27 · Oct 9
- Mount Carroll May 2 · Oct 7
- Kent Apr 27 · Oct 9
- Thomson Apr 13 · Oct 26
- Warren Apr 27 · Oct 9
Frequently asked questions
When is the last frost in Hanover, IL?
The median last spring frost in Hanover, IL is May 1. There is still about a 10% chance of frost after May 17, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Hanover, IL?
The median first fall frost is October 9, with about a 10% chance of frost before September 25.
How long is the growing season in Hanover, IL?
About 161 days between the median last spring frost and first fall frost.
What planting zone is Hanover, IL?
Hanover, IL is in USDA hardiness zone 5a.