Lacon, IL Frost Dates & Growing Season

The two dates every Lacon garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
Apr 20
~50% chance of frost after
First fall frost
Oct 17
~50% chance of frost before
Growing season
180 days
frost-free stretch
USDA zone
≈ 6a
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Apr 5 Apr 20 May 7
First fall frost Nov 1 Oct 17 Oct 3
Hard freeze (28°F), median last Apr 7 · first Oct 28

Computed from NOAA 1991–2020 climate normals at the LACON station. "Safe" means frost past that date happens only about one year in ten. Your exact garden can still run days either way with elevation and terrain — check your own ZIP with the frost date lookup.

Planting windows for Lacon

Computed from Lacon's own frost dates. Click any crop for the full zone-6 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Feb 23 – Mar 9 Apr 27 – May 4
🫑 Peppers Feb 9 – Feb 23 May 4 – May 11
🥬 Lettuce Mar 9 – Mar 23 Mar 23 – Apr 6 Mar 23 – Apr 20
🫛 Peas Mar 9 – Mar 23
🥕 Carrots Mar 30 – Apr 20
🥦 Broccoli Mar 2 – Mar 16 Mar 30 – Apr 13
🥬 Kale Mar 9 – Mar 23 Mar 23 – Apr 6 Mar 23 – Apr 6
🥒 Cucumbers Mar 23 – Mar 30 Apr 27 – May 4 Apr 27 – May 4
🥒 Zucchini Mar 23 – Mar 30 Apr 27 – May 4 Apr 27 – May 4
🫘 Green Beans (Bush) Apr 27 – May 4
🌽 Sweet Corn Apr 27 – May 4
🌿 Basil Mar 9 – Mar 23 Apr 27 – May 4 May 4 – May 11
🧄 Garlic Fall: Sep 5 – Oct 3

Want this for all 50 crops, or as a printable seed-shelf schedule? Use the planting calendar and the seed starting scheduler — both can use Lacon's dates automatically after a lookup.

Reading the season in Lacon

Roughly 180 frost-free days gives Lacon gardeners room for nearly every common vegetable. Warm-season crops go out after Apr 20; a fall garden sown in late summer matures comfortably before the Oct 17 frost.

Frequently asked questions

When is the last frost in Lacon, IL?

The average last spring frost in Lacon is around Apr 20, based on 1991–2020 climate normals. That's a median — about half of years see a later frost, so tender crops are safest going out a week or two after this date.

When is the first frost in Lacon, IL?

The average first fall frost in Lacon arrives around Oct 17. Crops still in the garden need to mature before then, and frost-tender plants need harvesting or protection as the date approaches.

How long is the growing season in Lacon?

About 180 frost-free days on average, from Apr 20 to Oct 17. That fits nearly all common vegetables, though the longest-season melons and sweet potatoes benefit from transplants.

What USDA zone is Lacon in?

USDA zone 6a on the 2023 Plant Hardiness Zone Map. Note that zones describe winter cold, not frost timing — these frost dates are the numbers to plan plantings around.