Alden, IL frost dates
Last spring frostApr 25median date
First fall frostOct 22median date
Growing season180 daysfrost-free
Hardiness zone5bZone 5b
How Alden compares
- In 8 years out of 10, the last spring frost in Alden falls between April 11 and May 9, a 28-day window. The first fall frost falls between October 7 and November 4.
- The median last frost is 8 days later than the Illinois median of Apr 17.
- Its 180-day growing season is longer than 29% of the 1,287 Illinois places with a regular frost season (state median 187 days).
- The last frost is 6 days earlier than the zone 5b median of May 1. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5b chart.
- The weather station records an average of 136 nights a year at or below 32°F.
- Compared with Elgin, IL, 34 km away, the last frost here is 1 day earlier than there and the growing season is 5 days longer.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 11 |
| 50% (median) | April 25 |
| 10% (safe for tender plants) | May 9 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | October 7 |
| 50% (median) | October 22 |
| 90% (late) | November 4 |
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 Alden, IL
Alden, IL frost dates — last frost Apr 25, first frost Oct 22, zone 5b. whenisthelastfrost.com
Crop
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Start indoors: Jan 31 to Feb 14Transplant outside: Mar 28 to Apr 11
Start indoors: Feb 14 to Feb 28Transplant outside: May 9 to May 23
Start indoors: Feb 14 to Feb 28Transplant outside: May 9 to May 23
Start indoors: Feb 28 to Mar 14Transplant outside: May 2 to May 16
Start indoors: Feb 28 to Mar 14Transplant outside: Apr 4 to Apr 18Sow outdoors: Mar 28 to May 2Plant for fall: Aug 27 to Sep 24
Start indoors: Feb 28 to Mar 14Transplant outside: Mar 28 to Apr 11Sow outdoors: Mar 28 to Apr 11Plant for fall: Aug 13 to Sep 3
Start indoors: Feb 28 to Mar 14Transplant outside: Apr 11 to Apr 25Plant for fall: Jul 16 to Aug 6
Start indoors: Feb 28 to Mar 14Transplant outside: Apr 4 to Apr 18Plant for fall: Jul 16 to Aug 6
Start indoors: Feb 28 to Mar 14Transplant outside: Apr 11 to Apr 25Plant for fall: Jul 16 to Aug 6
Start indoors: Mar 14 to Mar 28Transplant outside: May 16 to May 30Sow outdoors: May 16 to May 30
Start indoors: Mar 14 to Mar 28Transplant outside: May 2 to May 16
Sow outdoors: Mar 14 to Apr 4Plant for fall: Jul 30 to Aug 20
Sow outdoors: Mar 14 to Apr 4Plant for fall: Aug 27 to Sep 17
Sow outdoors: Mar 21 to May 2Plant for fall: Sep 10 to Oct 1
Start indoors: Mar 28 to Apr 4Transplant outside: May 9 to May 16Sow outdoors: May 2 to May 16Plant for fall: Aug 6 to Aug 20
Start indoors: Mar 28 to Apr 4Sow outdoors: May 2 to May 16Plant for fall: Aug 13 to Aug 27
Start indoors: Mar 28 to Apr 4Sow outdoors: May 2 to May 16
Start indoors: Mar 28 to Apr 4Transplant outside: May 9 to May 23
Sow outdoors: Apr 4 to May 2Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 4 to May 2Plant for fall: Aug 13 to Aug 27
Sow outdoors: Apr 4 to Apr 25
Sow outdoors: Apr 11 to May 9Plant for fall: Aug 13 to Aug 27
Sow outdoors: Apr 11 to May 2Plant for fall: Aug 27 to Sep 17
Sow outdoors: May 2 to May 23Plant for fall: Aug 6 to Aug 20
Sow outdoors: May 2 to May 16
Transplant outside: May 9 to May 30
Plant for fall: Oct 8 to Nov 12
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Alden, IL
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Jan 31 – Feb 14 | Mar 28 – Apr 11 | — | — |
| Peppers | Feb 14 – Feb 28 | May 9 – May 23 | — | — |
| Eggplant | Feb 14 – Feb 28 | May 9 – May 23 | — | — |
| Tomatoes | Feb 28 – Mar 14 | May 2 – May 16 | — | — |
| Lettuce | Feb 28 – Mar 14 | Apr 4 – Apr 18 | Mar 28 – May 2 | Aug 27 – Sep 24 |
| Kale | Feb 28 – Mar 14 | Mar 28 – Apr 11 | Mar 28 – Apr 11 | Aug 13 – Sep 3 |
| Broccoli | Feb 28 – Mar 14 | Apr 11 – Apr 25 | — | Jul 16 – Aug 6 |
| Cabbage | Feb 28 – Mar 14 | Apr 4 – Apr 18 | — | Jul 16 – Aug 6 |
| Cauliflower | Feb 28 – Mar 14 | Apr 11 – Apr 25 | — | Jul 16 – Aug 6 |
| Okra | Mar 14 – Mar 28 | May 16 – May 30 | May 16 – May 30 | — |
| Basil | Mar 14 – Mar 28 | May 2 – May 16 | — | — |
| Peas | — | — | Mar 14 – Apr 4 | Jul 30 – Aug 20 |
| Spinach | — | — | Mar 14 – Apr 4 | Aug 27 – Sep 17 |
| Radishes | — | — | Mar 21 – May 2 | Sep 10 – Oct 1 |
| Cucumbers | Mar 28 – Apr 4 | May 9 – May 16 | May 2 – May 16 | Aug 6 – Aug 20 |
| Zucchini & Summer Squash | Mar 28 – Apr 4 | — | May 2 – May 16 | Aug 13 – Aug 27 |
| Winter Squash & Pumpkins | Mar 28 – Apr 4 | — | May 2 – May 16 | — |
| Melons & Watermelon | Mar 28 – Apr 4 | May 9 – May 23 | — | — |
| Carrots | — | — | Apr 4 – May 2 | Jul 30 – Aug 13 |
| Beets | — | — | Apr 4 – May 2 | Aug 13 – Aug 27 |
| Potatoes | — | — | Apr 4 – Apr 25 | — |
| Swiss Chard | — | — | Apr 11 – May 9 | Aug 13 – Aug 27 |
| Cilantro | — | — | Apr 11 – May 2 | Aug 27 – Sep 17 |
| Green Beans | — | — | May 2 – May 23 | Aug 6 – Aug 20 |
| Sweet Corn | — | — | May 2 – May 16 | — |
| Sweet Potatoes | — | May 9 – May 30 | — | — |
| Garlic | — | — | — | Oct 8 – Nov 12 |
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 Crystal Lake 4nw, IL weather station, 9 km away (elevation 942 ft (287 m)).
Frost dates near Alden
- Woodstock Apr 25 · Oct 22
- Crystal Lake Apr 25 · Oct 22
- Wonder Lake May 1 · Oct 11
- Union Apr 28 · Oct 12
- Ringwood May 1 · Oct 11
- Marengo Apr 28 · Oct 12
- Hebron Apr 30 · Oct 13
- Mchenry May 1 · Oct 11
- Harvard Apr 28 · Oct 12
- Huntley Apr 25 · Oct 22
Frequently asked questions
When is the last frost in Alden, IL?
The median last spring frost in Alden, IL is April 25. There is still about a 10% chance of frost after May 9, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Alden, IL?
The median first fall frost is October 22, with about a 10% chance of frost before October 7.
How long is the growing season in Alden, IL?
About 180 days between the median last spring frost and first fall frost.
What planting zone is Alden, IL?
Alden, IL is in USDA hardiness zone 5b.