John Martin Dam, Colorado climate: Climate normals at a NOAA weather station
John Martin Dam's normal year runs from 16°F January nights to 95°F July afternoons, with 13.2 inches of precipitation and 10 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 12.7°C, January lows of −9°C, July highs of 35°C, 334 mm of precipitation a year.
- NOAA stationJohn Martin Dam
- Station IDUSC00054388
- Location38.06°N 102.93°W
- Elevation3,814 ft (1,163 m)
On October 23, the normal high in John Martin Dam is 69°F and the normal low 35°F, and the chance of measurable rain or snow is 11%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for John Martin Dam.
- Jan 46° 16°
- Feb 50° 20°
- Mar 61° 29°
- Apr 69° 38°
- May 79° 48°
- Jun 90° 59°
- Jul 95° 64°
- Aug 92° 62°
- Sep 85° 53°
- Oct 72° 38°
- Nov 58° 27°
- Dec 47° 18°
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 John Martin Dam each month?
July is the warmest month, with normal highs of 95°F; January the coldest, with normal lows of 16°F. The most precipitation falls in July (2.35 in), the least in January (0.24 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 46°F | 16°F | 31.3°F | 0.24 | 1.7 | 2 | <1 | 31 | 9 h 50 min |
| February | 50°F | 20°F | 35.1°F | 0.28 | 2.4 | 2 | <1 | 27 | 10 h 50 min |
| March | 61°F | 29°F | 44.8°F | 0.71 | 1.4 | 4 | <1 | 22 | 11 h 50 min |
| April | 69°F | 38°F | 53.3°F | 1.23 | 0.2 | 5 | 1 | 9 | 13 h 10 min |
| May | 79°F | 48°F | 63.4°F | 1.62 | 0.0 | 5 | 6 | 1 | 14 h 10 min |
| June | 90°F | 59°F | 74.6°F | 1.92 | 0.0 | 6 | 18 | <1 | 14 h 50 min |
| July | 95°F | 64°F | 79.4°F | 2.35 | 0.0 | 7 | 24 | <1 | 14 h 30 min |
| August | 92°F | 62°F | 77.2°F | 2.05 | 0.0 | 6 | 21 | <1 | 13 h 40 min |
| September | 85°F | 53°F | 68.8°F | 1.02 | 0.0 | 4 | 12 | <1 | 12 h 30 min |
| October | 72°F | 38°F | 54.9°F | 0.98 | 0.2 | 4 | 2 | 9 | 11 h 20 min |
| November | 58°F | 27°F | 42.4°F | 0.39 | 0.9 | 2 | <1 | 24 | 10 h 10 min |
| December | 47°F | 18°F | 32.0°F | 0.36 | 2.9 | 2 | <1 | 31 | 9 h 30 min |
| Year (annual) | 70°F | 39°F | 54.8°F | 13.15 | 9.7 | 48 | 83 | 153 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 8°C | −9°C | −0.4°C | 6 mm | 4 cm |
| February | 10°C | −7°C | 1.7°C | 7 mm | 6 cm |
| March | 16°C | −2°C | 7.1°C | 18 mm | 4 cm |
| April | 21°C | 3°C | 11.8°C | 31 mm | 1 cm |
| May | 26°C | 9°C | 17.4°C | 41 mm | 0 cm |
| June | 32°C | 15°C | 23.7°C | 49 mm | 0 cm |
| July | 35°C | 18°C | 26.3°C | 60 mm | 0 cm |
| August | 33°C | 17°C | 25.1°C | 52 mm | 0 cm |
| September | 29°C | 12°C | 20.4°C | 26 mm | 0 cm |
| October | 22°C | 3°C | 12.7°C | 25 mm | 1 cm |
| November | 15°C | −3°C | 5.8°C | 10 mm | 2 cm |
| December | 8°C | −8°C | 0.0°C | 9 mm | 7 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00054388; 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 John Martin Dam?
Normal highs sit between 65°F and 85°F in April, May, September and October. Of those, October has the fewest days with rain (4).
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 USC00054388.
When is the last frost at John Martin Dam?
In John Martin Dam, the last spring frost (32°F) comes after April 24 in half of years and after May 8 in one year in ten; the first autumn frost comes before October 15 in half of years and before October 2 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
- April 241 year in 10 after May 8; 9 in 10 after April 9
- First autumn frost, half of years before
- October 151 year in 10 before October 2; 9 in 10 before October 26
NOAA puts the median frost-free season at 172 days, and the season without a hard freeze (28°F) at 193 days.
A hard freeze (28°F) comes after April 11 in half of springs and before October 23 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts John Martin Dam in zone 6a in ZIP code 81057, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 6a: the coldest night of a typical year reaches −8°F (17 complete years).
Frost dates for every NOAA station in Colorado · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00054388; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. 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 John Martin Dam?
In a normal year in John Martin Dam, 83 days a year reach 90°F (21 of them 100°F or more), 153 nights fall to 32°F or colder and 48 days bring measurable precipitation.
- Days at 90°F or more
- 83a normal year
- Days at 100°F or more
- 21a normal year
- Nights at 32°F or colder
- 153a normal year
- Days that stay below freezing
- 16high of 32°F or less
- Days with 0.01 inch of precipitation
- 48a normal year
- Days with 1 inch of snow or more
- 2a normal year
The highest temperature in this station's record (since 1941) is 115°F, on July 20, 2019; the lowest is −27°F, on February 15, 2021.
The wettest calendar year on that record is 1990, with 20.17 in; the snowiest season is 1947–48, with 52.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00054388; records: ACIS (NOAA Regional Climate Centers), station USC00054388. Records use complete months only; a month missing more than three days is left out.
How sunny is it at John Martin Dam?
Over a year 84% of the sunlight that would reach the ground under clear skies gets through the clouds at John Martin Dam, 5.0 kWh per square metre a day. July is the sunniest month (90%) and February the cloudiest (76%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 79% | 2.7 |
| February | 76% | 3.5 |
| March | 80% | 4.9 |
| April | 80% | 6.0 |
| May | 82% | 6.9 |
| June | 88% | 7.6 |
| July | 90% | 7.5 |
| August | 89% | 6.6 |
| September | 87% | 5.5 |
| October | 83% | 4.1 |
| November | 83% | 3.0 |
| December | 78% | 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 John Martin Dam record?
A normal year at John Martin Dam brings 5,101 heating degree days, 5% fewer than the median U.S. place (5,373), and 1,404 cooling degree days, 55% more than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,963 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,045 | 0 |
| February | 837 | 0 |
| March | 626 | 1 |
| April | 357 | 7 |
| May | 133 | 84 |
| June | 12 | 300 |
| July | 1 | 446 |
| August | 3 | 382 |
| September | 57 | 170 |
| October | 328 | 15 |
| November | 680 | 0 |
| December | 1,023 | 0 |
| Year (annual) | 5,101 | 1,404 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00054388. 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.
Have recent years at John Martin Dam been warmer than normal?
2025 averaged 55.0°F, 0.2°F above the 1991-2020 normal of 54.8°F. 2 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 54.6°F | −0.2°F | 10.35 | 6.3 |
| 2022 | 53.4°F | −1.4°F | 14.47 | 8.7 |
| 2023 | 53.7°F | −1.1°F | 16.22 | – |
| 2024 | 55.8°F | +1.0°F | 14.47 | – |
| 2025 | 55.0°F | +0.2°F | – | – |
Over 42 complete years from 1949 to 2025, the station's annual mean temperature rose at a fitted 2.0°F per century (+0.11°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00054388; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does John Martin Dam's climate compare?
John Martin Dam is warmer than 124 of the 125 places with their own NOAA record in Colorado, and wetter than 31. Across the 7,247 U.S. stations with normals, its annual mean of 54.8°F is warmer than 59%.
In the Köppen classification computed from these normals, John Martin Dam is BSk: cold semi-arid steppe. 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 John Martin Dam share this climate record?
2 places have no NOAA station with 1991-2020 normals of their 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.
- Hasty, CO94 people · 3 mi NW
- McClave, CO74 people · 6 mi NE
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 John Martin Dam's climate
What is the coldest month at John Martin Dam?
January, with a normal high of 46°F and a normal low of 16°F. The warmest is July (95°F by day, 64°F at night).
Does it snow at John Martin Dam?
Yes: 10 inches in a normal year, falling on 4 days with 0.1 inch or more, the most in December (2.9 inches).
What is the rainiest month at John Martin Dam?
July, with 2.35 in of precipitation in a normal year; the driest is January with 0.24 in.
What plant hardiness zone is John Martin Dam in?
The USDA's 2023 map puts John Martin Dam in zone 6a in ZIP code 81057, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches −8°F (17 years, 1991-2020): zone 6a.
How late can frost come at John Martin Dam?
In half of years the last 32°F night comes after April 24; in one year in ten it comes after May 8. Waiting until May 8 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Colorado climateThe statewide normals and every place in the state
- Lamar, CO13 miles from this station, 54.0°F a year
- Las Animas, CO16 miles from this station, 54.5°F a year
- Eads, CO30 miles from this station, 52.4°F a year
- La Junta, CO32 miles from this station, 54.8°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made