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Colorado · NOAA station USC00050756

Frost dates for Black Forest 6wnw, CO

At Black Forest 6wnw, the median last spring frost (32°F) is May 11 and the median first fall frost is Oct 6, for a typical growing season of 147 days. For a 90% chance that the last frost has passed, wait until May 25. Nearby ZIP codes are in USDA hardiness zone 5b.

  • May 11Last spring frost (median)50% chance of 32°F after this date
  • May 25Safer planting date10% chance of 32°F after this date
  • Oct 6First fall frost (median)50% chance of 32°F by this date
  • 147 daysGrowing season (median)between 32°F freezes

Planting date calculator

Pick how much frost risk you accept and how many weeks before or after the last frost your seed packet says to plant.

From your seed packet, e.g. “start 6 weeks before last frost”.

–Last spring frost
–First fall frost
–Your planting date
–Hardiness zone

Last spring frost dates

The chance that the temperature drops to the threshold after each date.

Black Forest 6wnw: last spring freeze by temperature
Temperature90% chance later50% chance later10% chance later
36°FMay 10May 23Jun 5
32°FApr 30May 11May 25
28°FApr 19May 2May 16
24°FApr 6Apr 22May 8

First fall frost dates

The chance that the temperature has dropped to the threshold by each date.

Black Forest 6wnw: first fall freeze by temperature
Temperature10% chance by50% chance by90% chance by
36°FSep 17Sep 29Oct 10
32°FSep 25Oct 6Oct 19
28°FOct 3Oct 16Oct 29
24°FOct 11Oct 24Nov 7

Growing season length

Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.

Black Forest 6wnw: growing season by temperature
Temperature9 in 10 years at least5 in 10 years at least1 in 10 years at least
36°F110 days129 days147 days
32°F128 days147 days164 days
28°F145 days164 days181 days
24°F165 days183 days204 days

Chance of a freeze in any year

Black Forest 6wnw: probability of at least one day at or below each temperature
TemperatureChance per year
36°F100%
32°F100%
28°F100%
24°F100%

ZIP codes whose closest station is this one

ZIP codes near Black Forest 6wnw with 2023 USDA hardiness zones
ZIPHardiness zoneAvg. extreme lowDistance
809215b-15 to -10°F4 km
809085b-15 to -10°F10 km

Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.

About this station

  • NOAA station ID USC00050756, at 39.0294, -104.8017, elevation 2120 m (6,957 ft).
  • Data quality: Representative (10+ years), 11 years of freeze data.
  • Average days per year at or below 32°F: 162.
  • Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.

Nearby weather stations

Sources

Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.

All Colorado stations · How frost dates are calculated