San Luis, Colorado climate: Normal weather by month, frost dates and records
San Luis's normal year runs from 6°F January nights to 82°F July afternoons, with 9.0 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 6.7°C, January lows of −14°C, July highs of 28°C, 229 mm of precipitation a year.
- NOAA stationSan Luis (1 mi S)
- Station IDUSC00057430
- Location37.20°N 105.42°W
- Elevation7,943 ft (2,421 m)
- Population628
On October 23, the normal high in San Luis is 60°F and the normal low 26°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 San Luis.
- Jan 37° 6°
- Feb 41° 12°
- Mar 52° 23°
- Apr 58° 27°
- May 68° 35°
- Jun 79° 42°
- Jul 82° 48°
- Aug 79° 47°
- Sep 74° 39°
- Oct 63° 28°
- Nov 49° 18°
- Dec 39° 9°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in San Luis each month?
July is the warmest month, with normal highs of 82°F; January the coldest, with normal lows of 6°F. The most precipitation falls in July (1.51 in), the least in March (0.35 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 37°F | 6°F | 21.6°F | 0.38 | 2 | <1 | 31 | 9 h 50 min |
| February | 41°F | 12°F | 26.7°F | 0.50 | 4 | <1 | 28 | 10 h 50 min |
| March | 52°F | 23°F | 37.4°F | 0.35 | 3 | <1 | 30 | 11 h 50 min |
| April | 58°F | 27°F | 42.6°F | 0.56 | 3 | <1 | 24 | 13 h 10 min |
| May | 68°F | 35°F | 51.2°F | 0.73 | 3 | <1 | 10 | 14 h 10 min |
| June | 79°F | 42°F | 60.4°F | 0.79 | 4 | <1 | 1 | 14 h 40 min |
| July | 82°F | 48°F | 65.0°F | 1.51 | 7 | 1 | <1 | 14 h 30 min |
| August | 79°F | 47°F | 63.3°F | 1.29 | 9 | <1 | <1 | 13 h 40 min |
| September | 74°F | 39°F | 56.5°F | 1.04 | 4 | <1 | 5 | 12 h 30 min |
| October | 63°F | 28°F | 45.6°F | 0.94 | 4 | <1 | 23 | 11 h 20 min |
| November | 49°F | 18°F | 33.4°F | 0.50 | 2 | <1 | 29 | 10 h 10 min |
| December | 39°F | 9°F | 23.7°F | 0.41 | 3 | <1 | 31 | 9 h 40 min |
| Year (annual) | 60°F | 28°F | 44.0°F | 9.00 | 47 | 2 | 211 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 3°C | −14°C | −5.8°C | 10 mm |
| February | 5°C | −11°C | −2.9°C | 13 mm |
| March | 11°C | −5°C | 3.0°C | 9 mm |
| April | 15°C | −3°C | 5.9°C | 14 mm |
| May | 20°C | 1°C | 10.7°C | 19 mm |
| June | 26°C | 5°C | 15.8°C | 20 mm |
| July | 28°C | 9°C | 18.3°C | 38 mm |
| August | 26°C | 9°C | 17.4°C | 33 mm |
| September | 23°C | 4°C | 13.6°C | 26 mm |
| October | 17°C | −2°C | 7.6°C | 24 mm |
| November | 10°C | −8°C | 0.8°C | 13 mm |
| December | 4°C | −13°C | −4.6°C | 10 mm |
NOAA publishes no 1991-2020 snowfall normal for this station, and no record within 25 miles keeps one, so snow is left out here rather than estimated.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00057430; 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.
When is the best weather to visit San Luis?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, May has the fewest days with rain (3).
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 USC00057430.
When is the last frost in San Luis?
In San Luis, the last spring frost (32°F) comes after May 31 in half of years and after June 14 in one year in ten; the first autumn frost comes before September 23 in half of years and before September 10 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
- May 311 year in 10 after June 14; 9 in 10 after May 14
- First autumn frost, half of years before
- September 231 year in 10 before September 10; 9 in 10 before October 5
NOAA puts the median frost-free season at 115 days, and the season without a hard freeze (28°F) at 139 days.
A hard freeze (28°F) comes after May 13 in half of springs and before September 30 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts San Luis in zone 5b in ZIP code 81152, 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 USC00057430; 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 in San Luis?
In a normal year in San Luis, 2 days a year reach 90°F, 211 nights fall to 32°F or colder and 47 days bring measurable precipitation.
- Days at 90°F or more
- 2a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 211a normal year
- Days that stay below freezing
- 29high of 32°F or less
- Days with 0.01 inch of precipitation
- 47a normal year
Source: NOAA NCEI 1991-2020 annual normals, station USC00057430.
How sunny is San Luis?
Over a year 83% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around San Luis, 5.3 kWh per square metre a day. October is the sunniest month (86%) and April the cloudiest (80%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 85% | 3.1 |
| February | 85% | 4.2 |
| March | 81% | 5.2 |
| April | 80% | 6.3 |
| May | 82% | 7.2 |
| June | 85% | 7.8 |
| July | 80% | 6.9 |
| August | 82% | 6.4 |
| September | 86% | 5.7 |
| October | 86% | 4.5 |
| November | 85% | 3.3 |
| December | 83% | 2.7 |
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 much heating and cooling does San Luis need?
A normal year in San Luis brings 7,719 heating degree days, 44% more than the median U.S. place (5,373), and 75 cooling degree days, 92% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,542 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,344 | 0 |
| February | 1,072 | 0 |
| March | 856 | 0 |
| April | 671 | 0 |
| May | 428 | 1 |
| June | 151 | 11 |
| July | 41 | 43 |
| August | 70 | 19 |
| September | 256 | 1 |
| October | 601 | 0 |
| November | 950 | 0 |
| December | 1,279 | 0 |
| Year (annual) | 7,719 | 75 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00057430. 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 San Luis's climate compare?
San Luis is warmer than 37 of the other 124 places with their own NOAA record in Colorado, and wetter than 6. Across the 7,247 U.S. stations with normals, its annual mean of 44.0°F is warmer than 15%.
In the Köppen classification computed from these normals, San Luis 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 San Luis share this climate record?
3 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.
- Costilla, NM498 people · 16 mi S
- Stonewall Gap, CO61 people · 22 mi E
- San Acacio, CO23 people · 8 mi W
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 San Luis's climate
What is the coldest month in San Luis?
January, with a normal high of 37°F and a normal low of 6°F. The warmest is July (82°F by day, 48°F at night).
What is the rainiest month in San Luis?
July, with 1.51 in of precipitation in a normal year; the driest is March with 0.35 in.
What plant hardiness zone is San Luis in?
The USDA's 2023 map puts San Luis in zone 5b in ZIP code 81152, the nearest ZIP area.
How late can frost come in San Luis?
In half of years the last 32°F night comes after May 31; in one year in ten it comes after June 14. Waiting until June 14 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Colorado climateThe statewide normals and every place in the state
- Blanca, CO21 miles from this station, 43.5°F a year
- Manassa, CO29 miles from this station, 43.8°F a year
- Alamosa, CO29 miles from this station, 42.3°F a year
- Cerro, NM33 miles from this station, 45.1°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made