Last frost date in Littleton, CO

Average last frost
May 2

The average last frost in Littleton is May 2. By May 17 the chance of another 32°F night drops to 1 in 10. The first fall frost usually arrives about October 11, which leaves 160 frost-free days. An early freeze before September 27 happens one year in ten.

Safe after (10% risk)
May 17
Average first frost
Oct 11
Frost-free season
160 days
Hard freeze (28°F) ends
Apr 23
Next 7 nights in Littleton

Frost possible in low spots Mon night, low 36°F

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

  1. ThuOct 2255°
  2. FriOct 2347°
  3. SatOct 2439°
  4. SunOct 2538°
  5. MonOct 2636°possible frost
  6. TueOct 2737°
  7. WedOct 2838°
JanFebMarAprMayJunJulAugSepOctNovDecLast frost May 2First frost Oct 11160 frost-free daysBlue: chance of 32°F frost. Green: average frost-free season.JFMAMJJASOND160 frost-free days
Frost risk through the year at Marston Fltr Plt, 3.2 miles from Littleton.

Planting calendar for Littleton

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 9–May 23
PumpkinsMay 16–May 30
SunflowersMay 2–May 23
CucumbersMay 16–May 23
CornMay 9–May 23
Sweet potatoesMay 23–Jun 6
WatermelonMay 16–May 30
Green beansMay 9–May 30
ZucchiniMay 9–May 23
OkraMay 23–Jun 6
PeppersMay 16–May 30
BasilMay 9–May 23
Butternut squashMay 9–May 23
CantaloupeMay 16–May 30
EggplantMay 16–May 30
Cool-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
PotatoesApr 4–Apr 18
OnionsMar 21–Apr 11
CarrotsApr 11–May 16
LettuceApr 18–May 9
BroccoliApr 4–Apr 18
BeetsApr 4–May 16
PeasMar 21–Apr 4
CabbageApr 4–Apr 18
RadishesMar 28–May 9
Brussels sproutsApr 18–May 2
SpinachMar 21–Apr 11
CilantroApr 18–May 9
KaleApr 4–Apr 18
Collard greensApr 4–Apr 18
TurnipsApr 4–Apr 18
DillMay 2–May 16
CeleryMay 9–May 16
CauliflowerApr 18–May 2
LeeksApr 18–May 2
Swiss chardApr 18–May 16
ParsleyApr 18–May 9
Fall bulbs and garlic
JanFebMarAprMayJunJulAugSepOctNovDec
Tulip bulbsSep 27–Nov 1
GarlicSep 20–Oct 25
Daffodil bulbsSep 13–Oct 25
Perennials
JanFebMarAprMayJunJulAugSepOctNovDec
StrawberriesApr 4–Apr 18
AsparagusApr 4–Apr 18

Frost probabilities

ThresholdSpring, 90% chance laterSpring, 50%Spring, 10%Fall, 10% chance earlierFall, 50%Fall, 90%
Light frost, 32°FApr 20May 2May 17Sep 27Oct 11Oct 23
Hard freeze, 28°FApr 8Apr 23May 7Oct 6Oct 21Nov 5

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 Marston Fltr Plt (USC00055402) sits 3.2 miles from the center of Littleton at 5,610 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 Littleton, CO?

The average last frost date in Littleton is May 2, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after May 17.

When is the first frost in Littleton?

The first frost in fall usually comes around October 11. One year in ten it arrives before September 27.

How long is the growing season in Littleton?

About 160 days between the average last and first frost.

When should I plant tomatoes in Littleton?

Plant tomato seedlings outside from May 9 to May 23. Start seeds indoors six to eight weeks earlier.

Nearby in Colorado

All 34 cities in Colorado