Rock Island L&d 15, IL Frost Dates & Growing Season

The two dates every Rock Island L&d 15 garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
Apr 19
~50% chance of frost after
First fall frost
Oct 22
~50% chance of frost before
Growing season
186 days
frost-free stretch
USDA zone
≈ 5b
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Apr 6 Apr 19 May 4
First fall frost Nov 2 Oct 22 Oct 7
Hard freeze (28°F), median last Apr 8 · first Oct 31

Computed from NOAA 1991–2020 climate normals at the ROCK ISLAND L&D 15 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 Rock Island L&d 15

Computed from Rock Island L&d 15's own frost dates. Click any crop for the full zone-5 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Feb 22 – Mar 8 Apr 26 – May 3
🫑 Peppers Feb 8 – Feb 22 May 3 – May 10
🥬 Lettuce Mar 8 – Mar 22 Mar 22 – Apr 5 Mar 22 – Apr 19
🫛 Peas Mar 8 – Mar 22
🥕 Carrots Mar 29 – Apr 19
🥦 Broccoli Mar 1 – Mar 15 Mar 29 – Apr 12
🥬 Kale Mar 8 – Mar 22 Mar 22 – Apr 5 Mar 22 – Apr 5
🥒 Cucumbers Mar 22 – Mar 29 Apr 26 – May 3 Apr 26 – May 3
🥒 Zucchini Mar 22 – Mar 29 Apr 26 – May 3 Apr 26 – May 3
🫘 Green Beans (Bush) Apr 26 – May 3
🌽 Sweet Corn Apr 26 – May 3
🌿 Basil Mar 8 – Mar 22 Apr 26 – May 3 May 3 – May 10
🧄 Garlic Fall: Sep 10 – Oct 8

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 Rock Island L&d 15's dates automatically after a lookup.

Reading the season in Rock Island L&d 15

Roughly 186 frost-free days gives Rock Island L&d 15 gardeners room for nearly every common vegetable. Warm-season crops go out after Apr 19; a fall garden sown in late summer matures comfortably before the Oct 22 frost.

Frequently asked questions

When is the last frost in Rock Island L&d 15, IL?

The average last spring frost in Rock Island L&d 15 is around Apr 19, 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 Rock Island L&d 15, IL?

The average first fall frost in Rock Island L&d 15 arrives around Oct 22. 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 Rock Island L&d 15?

About 186 frost-free days on average, from Apr 19 to Oct 22. That fits nearly all common vegetables, though the longest-season melons and sweet potatoes benefit from transplants.

What USDA zone is Rock Island L&d 15 in?

USDA zone 5b 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.