Green Mount Dam, Colorado climate: Climate normals at a NOAA weather station
Green Mount Dam's normal year runs from 4°F January nights to 79°F July afternoons, with 16.5 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 3.7°C, January lows of −16°C, July highs of 26°C, 418 mm of precipitation a year.
- NOAA stationGreen Mount Dam
- Station IDUSC00053592
- Location39.88°N 106.33°W
- Elevation7,740 ft (2,359 m)
On October 23, the normal high in Green Mount Dam is 52°F and the normal low 24°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Green Mount Dam.
- Jan 28° 4°
- Feb 33° 7°
- Mar 42° 15°
- Apr 51° 24°
- May 61° 32°
- Jun 74° 39°
- Jul 79° 44°
- Aug 76° 43°
- Sep 69° 36°
- Oct 55° 26°
- Nov 40° 16°
- Dec 29° 6°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Green Mount Dam each month?
July is the warmest month, with normal highs of 79°F; January the coldest, with normal lows of 4°F. The most precipitation falls in April (1.95 in), the least in November (1.05 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 28°F | 4°F | 15.7°F | 1.13 | – | <1 | 31 | 9 h 40 min |
| February | 33°F | 7°F | 19.6°F | 1.06 | – | <1 | 28 | 10 h 40 min |
| March | 42°F | 15°F | 28.5°F | 1.21 | – | <1 | 31 | 11 h 50 min |
| April | 51°F | 24°F | 37.3°F | 1.95 | – | <1 | 28 | 13 h 10 min |
| May | 61°F | 32°F | 46.4°F | 1.66 | – | <1 | 16 | 14 h 20 min |
| June | 74°F | 39°F | 56.5°F | 1.06 | – | <1 | 4 | 15 h |
| July | 79°F | 44°F | 61.6°F | 1.57 | – | 1 | <1 | 14 h 50 min |
| August | 76°F | 43°F | 59.4°F | 1.63 | – | <1 | 1 | 13 h 50 min |
| September | 69°F | 36°F | 52.1°F | 1.46 | – | <1 | 12 | 12 h 30 min |
| October | 55°F | 26°F | 40.7°F | 1.40 | – | <1 | 25 | 11 h 10 min |
| November | 40°F | 16°F | 27.9°F | 1.05 | – | <1 | 30 | 10 h |
| December | 29°F | 6°F | 17.5°F | 1.28 | – | <1 | 31 | 9 h 20 min |
| Year (annual) | 53°F | 24°F | 38.6°F | 16.46 | – | 1 | 235 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | −2°C | −16°C | −9.1°C | 29 mm |
| February | 0°C | −14°C | −6.9°C | 27 mm |
| March | 6°C | −9°C | −1.9°C | 31 mm |
| April | 10°C | −4°C | 2.9°C | 50 mm |
| May | 16°C | 0°C | 8.0°C | 42 mm |
| June | 23°C | 4°C | 13.6°C | 27 mm |
| July | 26°C | 7°C | 16.4°C | 40 mm |
| August | 24°C | 6°C | 15.2°C | 41 mm |
| September | 20°C | 2°C | 11.2°C | 37 mm |
| October | 13°C | −3°C | 4.8°C | 36 mm |
| November | 4°C | −9°C | −2.3°C | 27 mm |
| December | −2°C | −14°C | −8.1°C | 33 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Kremmling (12 miles away), gets 52 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00053592; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
Which months are mildest at Green Mount Dam?
Normal highs sit between 65°F and 85°F in June, July, August and September.
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00053592.
When is the last frost at Green Mount Dam?
In Green Mount Dam, the last spring frost (32°F) comes after June 6 in half of years and after June 23 in one year in ten; the first autumn frost comes before September 14 in half of years and before August 31 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- June 61 year in 10 after June 23; 9 in 10 after May 24
- First autumn frost, half of years before
- September 141 year in 10 before August 31; 9 in 10 before September 26
NOAA puts the median frost-free season at 98 days, and the season without a hard freeze (28°F) at 124 days.
A hard freeze (28°F) comes after May 22 in half of springs and before September 25 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Green Mount Dam in zone 5a in ZIP code 80498, the nearest ZIP area.
Frost dates for every NOAA station in Colorado · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00053592; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get at Green Mount Dam?
In a normal year in Green Mount Dam, 1 day a year reaches 90°F and 235 nights fall to 32°F or colder.
- Days at 90°F or more
- 1a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 235a normal year
- Days that stay below freezing
- 70high of 32°F or less
The highest temperature in this station's record (since 1939) is 97°F, on July 13, 1954; the lowest is −46°F, on February 7, 1989.
The wettest calendar year on that record is 1945, with 22.37 in; the snowiest season is 1979–80, with 151.6 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00053592; records: ACIS (NOAA Regional Climate Centers), station USC00053592. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Green Mount Dam?
Over a year 77% of the sunlight that would reach the ground under clear skies gets through the clouds at Green Mount Dam, 4.8 kWh per square metre a day. March is the sunniest month (81%) and May the cloudiest (70%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 79% | 2.7 |
| February | 78% | 3.7 |
| March | 81% | 5.2 |
| April | 74% | 5.8 |
| May | 70% | 6.3 |
| June | 81% | 7.5 |
| July | 77% | 6.7 |
| August | 76% | 5.9 |
| September | 80% | 5.2 |
| October | 76% | 3.8 |
| November | 75% | 2.8 |
| December | 74% | 2.3 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How many heating and cooling degree days does Green Mount Dam record?
A normal year at Green Mount Dam brings 9,619 heating degree days, 79% more than the median U.S. place (5,373), and 25 cooling degree days, 97% fewer than the median (908). Nine months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,032 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,527 | 0 |
| February | 1,270 | 0 |
| March | 1,130 | 0 |
| April | 829 | 0 |
| May | 578 | 0 |
| June | 257 | 2 |
| July | 120 | 16 |
| August | 180 | 7 |
| September | 387 | 0 |
| October | 753 | 0 |
| November | 1,113 | 0 |
| December | 1,474 | 0 |
| Year (annual) | 9,619 | 25 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00053592. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
How does Green Mount Dam's climate compare?
Green Mount Dam is warmer than 13 of the 125 places with their own NOAA record in Colorado, and wetter than 76. Across the 7,247 U.S. stations with normals, its annual mean of 38.6°F is warmer than 4%.
In the Köppen classification computed from these normals, Green Mount Dam is Dfb: continental, no dry season, warm summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Green Mount Dam share this climate record?
Heeney has no NOAA station with 1991-2020 normals of its own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Heeney, CO93 people · 2 mi E
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Green Mount Dam's climate
What is the coldest month at Green Mount Dam?
January, with a normal high of 28°F and a normal low of 4°F. The warmest is July (79°F by day, 44°F at night).
Does it snow at Green Mount Dam?
Yes. NOAA publishes no 1991-2020 snowfall normal for the station; the nearest record that keeps one, Kremmling (12 miles away), records 52 inches of snow in a normal year.
What is the rainiest month at Green Mount Dam?
April, with 1.95 in of precipitation in a normal year; the driest is November with 1.05 in.
What plant hardiness zone is Green Mount Dam in?
The USDA's 2023 map puts Green Mount Dam in zone 5a in ZIP code 80498, the nearest ZIP area.
How late can frost come at Green Mount Dam?
In half of years the last 32°F night comes after June 6; in one year in ten it comes after June 23. Waiting until June 23 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Colorado climateThe statewide normals and every place in the state
- Kremmling, CO12 miles from this station, 38.5°F a year
- Williams Fork Dam, CO13 miles from this station, 38.2°F a year
- Vail, CO17 miles from this station, 37.9°F a year
- Dillon, CO24 miles from this station, 35.5°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made