Last frost date in Denver, CO

Average last frost

May 4

Expect the last frost in Denver around May 4. Frost after May 16 happens in only one year out of ten. The first fall frost usually arrives about October 8, which leaves 156 frost-free days. An early freeze before September 25 happens one year in ten.

Safe after (10% risk): May 16
Average first frost: Oct 8
Frost-free season: 156 days
Hard freeze (28°F) ends: Apr 22

Next 7 nights in Denver

No frost in the next 7 nights

Later than usual: the average first frost here is October 8.

National Weather Service forecast, updated Oct 22, 12:57 UTC

ThuOct 2257°
FriOct 2348°
SatOct 2440°
SunOct 2540°
MonOct 2638°
TueOct 2739°
WedOct 2841°

Frost risk through the year at Denver-stapleton, 0.6 miles from Denver.

Planting calendar for Denver

Windows count forward or back from the average frost dates above. Click a crop for dates across Colorado.

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost

Warm-season crops

JanFebMarAprMayJunJulAugSepOctNovDec

TomatoesMay 11–May 25

PumpkinsMay 18–Jun 1

SunflowersMay 4–May 25

CucumbersMay 18–May 25

CornMay 11–May 25

Sweet potatoesMay 25–Jun 8

WatermelonMay 18–Jun 1

Green beansMay 11–Jun 1

ZucchiniMay 11–May 25

OkraMay 25–Jun 8

PeppersMay 18–Jun 1

BasilMay 11–May 25

Butternut squashMay 11–May 25

CantaloupeMay 18–Jun 1

EggplantMay 18–Jun 1

Cool-season crops

JanFebMarAprMayJunJulAugSepOctNovDec

PotatoesApr 6–Apr 20

OnionsMar 23–Apr 13

CarrotsApr 13–May 18

LettuceApr 20–May 11

BroccoliApr 6–Apr 20

BeetsApr 6–May 18

PeasMar 23–Apr 6

CabbageApr 6–Apr 20

RadishesMar 30–May 11

Brussels sproutsApr 20–May 4

SpinachMar 23–Apr 13

CilantroApr 20–May 11

KaleApr 6–Apr 20

Collard greensApr 6–Apr 20

TurnipsApr 6–Apr 20

DillMay 4–May 18

CeleryMay 11–May 18

CauliflowerApr 20–May 4

LeeksApr 20–May 4

Swiss chardApr 20–May 18

ParsleyApr 20–May 11

Fall bulbs and garlic

JanFebMarAprMayJunJulAugSepOctNovDec

Tulip bulbsSep 24–Oct 29

GarlicSep 17–Oct 22

Daffodil bulbsSep 10–Oct 22

Perennials

JanFebMarAprMayJunJulAugSepOctNovDec

StrawberriesApr 6–Apr 20

AsparagusApr 6–Apr 20

Frost probabilities

Threshold	Spring, 90% chance later	Spring, 50%	Spring, 10%	Fall, 10% chance earlier	Fall, 50%	Fall, 90%
Light frost, 32°F	Apr 20	May 4	May 16	Sep 25	Oct 8	Oct 20
Hard freeze, 28°F	Apr 6	Apr 22	May 7	Oct 3	Oct 18	Oct 31

Read the spring 10% column as the date after which only one year in ten still gets frost. That is the safer date for tomatoes, peppers and basil.

Where these numbers come from

NOAA station Denver-stapleton (USW00023062) sits 0.6 miles from the center of Denver at 5,286 feet. Its averages cover 1991 to 2020. Low spots, valleys and open fields can keep getting frost a week or two after the station stops; city centers and lakeshores usually get less of it.

Questions

When is the last frost in Denver, CO?

The average last frost date in Denver is May 4, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after May 16.

When is the first frost in Denver?

The first frost in fall usually comes around October 8. One year in ten it arrives before September 25.

How long is the growing season in Denver?

About 156 days between the average last and first frost.

When should I plant tomatoes in Denver?

Plant tomato seedlings outside from May 11 to May 25. Start seeds indoors six to eight weeks earlier.

Nearby in Colorado

All 34 cities in Colorado