Frost Dates for Gross Rsvr, CO

Elevation: 2429 m

Frost Dates

Last Spring Frost (50%) A 50% chance that the last spring frost has already passed by this date. Most gardeners use this as their primary planting guide. May 24
First Fall Frost (50%) A 50% chance that the first fall frost has occurred by this date. Plan to harvest or protect tender plants before this date. September 23

30% Probability

Only a 30% chance of frost remaining by this date. Use these dates for a safer planting window, especially for tender plants sensitive to cold.
Last Spring Frost May 31
First Fall Frost September 17

Hard Freeze (28°F)

Last Spring Hard Freeze May 10
First Fall Hard Freeze October 3
39.94°N, 105.35°W © OpenStreetMap

Growing Season

122 Days May 24 to September 23

USDA Hardiness Zone

Hardiness zones indicate which perennial plants can survive winter in your area. For annual vegetables, frost dates and growing season length matter more than hardiness zone.
Zone 5b

Avg. annual minimum: −15 to −10°F

Learn more

Köppen Climate

The Köppen climate classification system categorizes climates based on temperature and precipitation patterns.
Dfb Warm-Summer Continental

Warm summers and cold, snowy winters. A shorter growing season than hot-summer continental. Hardy vegetables, root crops, and cool-season greens do well. Season extension is valuable.

Köppen climate map

Temperature

Avg High Avg Temp Avg Low Light Frost (32°F) Hard Frost (28°F)
Temperature table
Average monthly temperatures (°F)
Month Avg High Avg Temp Avg Low
January39°28°17°
February40°28°17°
March47°35°22°
April52°40°27°
May61°48°35°
June73°58°44°
July79°65°50°
August77°62°48°
September70°55°41°
October57°44°31°
November47°35°24°
December40°29°18°

Precipitation

Precipitation table
Average monthly precipitation (inches)
MonthPrecipitation
January3.1
February3.0
March4.8
April5.5
May4.4
June3.3
July3.3
August3.2
September3.6
October3.8
November3.9
December3.3

Sunrise / Sunset

Daylight Longest: 14h 50m · Shortest: 9h 10m
Sunrise and sunset table
Sunrise, sunset, and daylight on the 15th of each month (local solar time)
Month Sunrise Sunset Daylight
January7:16 AM4:44 PM9h 28m
February6:46 AM5:14 PM10h 29m
March6:09 AM5:51 PM11h 41m
April5:28 AM6:32 PM13h 04m
May4:54 AM7:06 PM14h 12m
June4:35 AM7:25 PM14h 49m
July4:43 AM7:17 PM14h 34m
August5:13 AM6:47 PM13h 35m
September5:53 AM6:07 PM12h 15m
October6:33 AM5:27 PM10h 55m
November7:08 AM4:52 PM9h 45m
December7:25 AM4:35 PM9h 11m

Nearby Stations

Coal Creek Canyon, CO June 5 - September 16 Boulder, COMay 6 - October 5 Ralston Rsvr, CO May 3 - October 14 Boulder 14 W, CO June 21 - September 2 Wheat Ridge 2, CO May 5 - October 5 Lakewood, COMay 3 - October 7

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