Frost Dates for Denver, CO 80219

Last spring frost May 9 · First fall frost October 1 · 145 frost-free days · USDA Zone 6a

Frost probability for 80219

Frost10%50%90%
Spring (last frost)May 24May 9April 24
Fall (first frost)September 18October 1October 14

Dates come from NOAA 1971–2000 freeze probabilities at the nearest reporting station (9.5 km away); the 50% date is the median year.

Frost dates by ZIP code in Denver, CO

ZIPLast spring frost (50%)First fall frost (50%)Zone
80219May 9October 16a
80229May 9October 16a
80233May 9October 16a
80239May 9October 16a
80249May 9October 16a
80221May 9October 16a
80210May 9October 16a
80211May 9October 16a
80220May 9October 16a
80231May 9October 16a
80204May 9October 16a
80228May 13September 296a
80227May 13September 296a
80260May 4October 26a
80205May 9October 16a
80226May 9October 16a
80238May 9October 16a
80247May 9October 16a
80234May 5October 16a
80209May 9October 16a
80214May 9October 16a
80206May 9October 16a
80222May 9October 16a
80237May 17September 276a
80232May 13September 296a
80203May 9October 16a
80207May 9October 16a
80212May 9October 16a
80215May 9October 16a
80224May 9October 16a
80223May 9October 16a
80218May 9October 16a
80202May 9October 16a
80216May 9October 16a
80236May 9October 16a
80246May 9October 16a
80230May 9October 16a
80235May 13September 296a
80290May 9October 16a
80264May 9October 1Zone 5b
80266May 9October 16a
80293May 9October 1Zone 5b
80294May 9October 1Zone 5b

Month by month in Denver

MonthWhat to do
JanuaryPlan your garden layout and order seeds. Research varieties suited to your frost dates.
FebruaryStart the slowest-growing crops indoors: onions, leeks, and celery (10–12 weeks before last frost).
MarchStart peppers and eggplant indoors 8–10 weeks before your last frost (around May 9). Start tomatoes about two weeks later, 6–8 weeks before last frost.
AprilStart herbs, basil, and squash indoors (4–6 weeks before frost). Direct sow peas, spinach, and lettuce if soil is workable.
MayLast frost around May 9. Transplant cold-hardy crops (broccoli, kale, cabbage). Harden off tomato and pepper seedlings.
JuneFrost has passed. Transplant tomatoes, peppers, and basil outdoors. Direct sow beans, cucumbers, squash, and zucchini.
JulySuccession plant lettuce and greens. Keep beds weeded and watered consistently.
AugustHarvest regularly to encourage production. Monitor for pests and disease.
SeptemberFirst fall frost approaching (around October 1). Transplant fall brassicas. Sow spinach, arugula, and radishes.
OctoberFirst frost around October 1. 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 145-day season

Frequently Asked Questions

What is the last frost date for Denver, CO (ZIP 80219)?

The median last spring frost date for Denver, CO (ZIP code 80219) is around May 9. 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 Denver, CO?

The median first fall frost date for Denver, CO is around October 1. 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 Denver, CO?

The frost-free growing season in Denver is about 145 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 Denver, CO?

Based on frost date patterns, Denver falls approximately in 6a. 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 Denver, CO?

Start tomato seeds indoors 6–8 weeks before your last frost date (around May 9). For Denver, that's roughly March 14 to March 28. Transplant outdoors 1–2 weeks after your last frost.

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