Rend Lake Dam, IL Frost Dates & Growing Season

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

Last spring frost
Apr 4
~50% chance of frost after
First fall frost
Oct 27
~50% chance of frost before
Growing season
206 days
frost-free stretch
USDA zone
≈ 7a
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Mar 21 Apr 4 Apr 19
First fall frost Nov 8 Oct 27 Oct 16
Hard freeze (28°F), median last Mar 26 · first Nov 5

Computed from NOAA 1991–2020 climate normals at the REND LAKE DAM 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 Rend Lake Dam

Computed from Rend Lake Dam's own frost dates. Click any crop for the full zone-7 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Feb 7 – Feb 21 Apr 11 – Apr 18
🫑 Peppers Jan 24 – Feb 7 Apr 18 – Apr 25
🥬 Lettuce Feb 21 – Mar 7 Mar 7 – Mar 21 Mar 7 – Apr 4
🫛 Peas Feb 21 – Mar 7
🥕 Carrots Mar 14 – Apr 4
🥦 Broccoli Feb 14 – Feb 28 Mar 14 – Mar 28
🥬 Kale Feb 21 – Mar 7 Mar 7 – Mar 21 Mar 7 – Mar 21
🥒 Cucumbers Mar 7 – Mar 14 Apr 11 – Apr 18 Apr 11 – Apr 18
🥒 Zucchini Mar 7 – Mar 14 Apr 11 – Apr 18 Apr 11 – Apr 18
🫘 Green Beans (Bush) Apr 11 – Apr 18
🌽 Sweet Corn Apr 11 – Apr 18
🌿 Basil Feb 21 – Mar 7 Apr 11 – Apr 18 Apr 18 – Apr 25
🧄 Garlic Fall: Sep 15 – Oct 13

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 Rend Lake Dam's dates automatically after a lookup.

Reading the season in Rend Lake Dam

With roughly 206 frost-free days, Rend Lake Dam gardens fit long-season crops — melons, winter squash, sweet potatoes — with room left for spring and fall rounds of greens and roots. The first frost around Oct 27 is late enough that fall planting is a full second season, not an afterthought.

Frequently asked questions

When is the last frost in Rend Lake Dam, IL?

The average last spring frost in Rend Lake Dam is around Apr 4, 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 Rend Lake Dam, IL?

The average first fall frost in Rend Lake Dam arrives around Oct 27. 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 Rend Lake Dam?

About 206 frost-free days on average, from Apr 4 to Oct 27. That comfortably fits long-season crops like melons and winter squash, plus spring and fall plantings of cool-season vegetables.

What USDA zone is Rend Lake Dam in?

USDA zone 7a 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.