Frost Dates for Ames, IA 50010

Last spring frost April 27 · First fall frost October 5 · 161 frost-free days · USDA Zone 5b

Frost probability for 50010

Frost10%50%90%
Spring (last frost)May 10April 27April 14
Fall (first frost)September 22October 5October 18

Dates come from NOAA 1971–2000 freeze probabilities at the nearest reporting station (22.3 km away); the 50% date is the median year.

Frost dates by ZIP code in Ames, IA

ZIPLast spring frost (50%)First fall frost (50%)Zone
50010April 27October 55b
50014April 26October 65b
50013April 26October 65b
50012April 26October 65b

Month by month in Ames

MonthWhat to do
JanuaryPlan your garden layout and order seeds. Research varieties suited to your frost dates.
FebruaryStart peppers and eggplant indoors 8–10 weeks before your last frost (around April 27). Start tomatoes about two weeks later, 6–8 weeks before last frost.
MarchStart herbs, basil, and squash indoors (4–6 weeks before frost). Direct sow peas, spinach, and lettuce if soil is workable.
AprilLast frost around April 27. Transplant cold-hardy crops (broccoli, kale, cabbage). Harden off tomato and pepper seedlings.
MayFrost has passed. Transplant tomatoes, peppers, and basil outdoors. Direct sow beans, cucumbers, squash, and zucchini.
JuneSuccession plant lettuce and greens. Keep beds weeded and watered consistently.
JulyHarvest regularly to encourage production. Monitor for pests and disease.
AugustMidsummer: harvest beans, zucchini, cucumbers. Start brassica seeds indoors for fall.
SeptemberFirst fall frost approaching (around October 5). Transplant fall brassicas. Sow spinach, arugula, and radishes.
OctoberFirst frost around October 5. Harvest tomatoes and peppers before frost. Cover cold-hardy crops with row covers to extend the season.
NovemberHarvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year.
DecemberClean up spent plants. Add compost to beds. Rest, review, and plan next year's garden.

What grows in a 161-day season

Frequently Asked Questions

What is the last frost date for Ames, IA (ZIP 50010)?

The median last spring frost date for Ames, IA (ZIP code 50010) is around April 27. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area.

What is the first fall frost date in Ames, IA?

The median first fall frost date for Ames, IA is around October 5. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses.

How long is the growing season in Ames, IA?

The frost-free growing season in Ames is about 161 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side.

What USDA hardiness zone is Ames, IA?

Based on frost date patterns, Ames falls approximately in 5b. USDA hardiness zones are determined by average annual minimum winter temperatures and guide both plant selection and planting timing for your location.

When should I start tomatoes indoors in Ames, IA?

Start tomato seeds indoors 6–8 weeks before your last frost date (around April 27). For Ames, that's roughly March 2 to March 16. Transplant outdoors 1–2 weeks after your last frost.

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