Allison, IA Frost Dates & Growing Season

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

Last spring frost
Apr 27
~50% chance of frost after
First fall frost
Oct 8
~50% chance of frost before
Growing season
164 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 12 Apr 27 May 8
First fall frost Oct 22 Oct 8 Sep 24
Hard freeze (28°F), median last Apr 16 · first Oct 20

Computed from NOAA 1991–2020 climate normals at the ALLISON 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 Allison

Computed from Allison'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 Mar 2 – Mar 16 May 4 – May 11
🫑 Peppers Feb 16 – Mar 2 May 11 – May 18
🥬 Lettuce Mar 16 – Mar 30 Mar 30 – Apr 13 Mar 30 – Apr 27
🫛 Peas Mar 16 – Mar 30
🥕 Carrots Apr 6 – Apr 27
🥦 Broccoli Mar 9 – Mar 23 Apr 6 – Apr 20
🥬 Kale Mar 16 – Mar 30 Mar 30 – Apr 13 Mar 30 – Apr 13
🥒 Cucumbers Mar 30 – Apr 6 May 4 – May 11 May 4 – May 11
🥒 Zucchini Mar 30 – Apr 6 May 4 – May 11 May 4 – May 11
🫘 Green Beans (Bush) May 4 – May 11
🌽 Sweet Corn May 4 – May 11
🌿 Basil Mar 16 – Mar 30 May 4 – May 11 May 11 – May 18
🧄 Garlic Fall: Aug 27 – Sep 24

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 Allison's dates automatically after a lookup.

Reading the season in Allison

Roughly 164 frost-free days gives Allison gardeners room for nearly every common vegetable. Warm-season crops go out after Apr 27; a fall garden sown in late summer matures comfortably before the Oct 8 frost.

Frequently asked questions

When is the last frost in Allison, IA?

The average last spring frost in Allison is around Apr 27, 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 Allison, IA?

The average first fall frost in Allison arrives around Oct 8. 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 Allison?

About 164 frost-free days on average, from Apr 27 to Oct 8. That fits nearly all common vegetables, though the longest-season melons and sweet potatoes benefit from transplants.

What USDA zone is Allison 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.