San Jon, New Mexico climate: Normal weather by month, frost dates and records
San Jon's normal year runs from 26°F January nights to 95°F July afternoons, with 17.0 inches of precipitation and 17 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 15.7°C, January lows of −4°C, July highs of 35°C, 431 mm of precipitation a year.
- NOAA stationSan Jon
- Station IDUSC00297867
- Location35.11°N 103.33°W
- Elevation4,230 ft (1,289 m)
- From the centerunder 1 mile
- Population185
On October 23, the normal high in San Jon is 73°F and the normal low 43°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 Jon.
- Jan 55° 26°
- Feb 59° 28°
- Mar 68° 36°
- Apr 75° 43°
- May 84° 53°
- Jun 93° 62°
- Jul 95° 67°
- Aug 93° 65°
- Sep 87° 58°
- Oct 76° 45°
- Nov 64° 34°
- Dec 55° 26°
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 Jon each month?
July is the warmest month, with normal highs of 95°F; January the coldest, with normal lows of 26°F. The most precipitation falls in July (2.69 in), the least in February (0.43 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 55°F | 26°F | 40.2°F | 0.66 | 4.3 | 3 | <1 | 25 | 10 h |
| February | 59°F | 28°F | 43.9°F | 0.43 | 1.8 | 2 | <1 | 20 | 10 h 50 min |
| March | 68°F | 36°F | 51.6°F | 1.09 | 2.1 | 3 | <1 | 12 | 11 h 50 min |
| April | 75°F | 43°F | 59.2°F | 1.09 | 0.9 | 3 | 1 | 4 | 13 h |
| May | 84°F | 53°F | 68.3°F | 1.77 | 0.1 | 5 | 9 | <1 | 14 h |
| June | 93°F | 62°F | 77.7°F | 2.14 | 0.0 | 6 | 21 | <1 | 14 h 30 min |
| July | 95°F | 67°F | 81.0°F | 2.69 | 0.0 | 7 | 25 | <1 | 14 h 20 min |
| August | 93°F | 65°F | 79.2°F | 2.42 | 0.0 | 7 | 22 | <1 | 13 h 30 min |
| September | 87°F | 58°F | 72.3°F | 1.40 | 0.0 | 5 | 11 | <1 | 12 h 30 min |
| October | 76°F | 45°F | 60.7°F | 1.73 | 0.5 | 4 | 2 | 2 | 11 h 20 min |
| November | 64°F | 34°F | 49.1°F | 0.72 | 2.0 | 3 | <1 | 13 | 10 h 20 min |
| December | 55°F | 26°F | 40.3°F | 0.82 | 5.4 | 3 | <1 | 24 | 9 h 50 min |
| Year (annual) | 75°F | 45°F | 60.3°F | 16.96 | 17.1 | 51 | 90 | 100 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 13°C | −4°C | 4.6°C | 17 mm | 11 cm |
| February | 15°C | −2°C | 6.6°C | 11 mm | 5 cm |
| March | 20°C | 2°C | 10.9°C | 28 mm | 5 cm |
| April | 24°C | 6°C | 15.1°C | 28 mm | 2 cm |
| May | 29°C | 11°C | 20.2°C | 45 mm | 0 cm |
| June | 34°C | 17°C | 25.4°C | 54 mm | 0 cm |
| July | 35°C | 19°C | 27.2°C | 68 mm | 0 cm |
| August | 34°C | 18°C | 26.2°C | 61 mm | 0 cm |
| September | 30°C | 14°C | 22.4°C | 36 mm | 0 cm |
| October | 24°C | 7°C | 15.9°C | 44 mm | 1 cm |
| November | 18°C | 1°C | 9.5°C | 18 mm | 5 cm |
| December | 13°C | −3°C | 4.6°C | 21 mm | 14 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00297867; 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 Jon?
Normal highs sit between 65°F and 85°F in March, April, May and October. Of those, March 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 USC00297867.
When is the last frost in San Jon?
In San Jon, the last spring frost (32°F) comes after April 18 in half of years and after May 3 in one year in ten; the first autumn frost comes before October 24 in half of years and before October 11 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 181 year in 10 after May 3; 9 in 10 after April 1
- First autumn frost, half of years before
- October 241 year in 10 before October 11; 9 in 10 before November 4
NOAA puts the median frost-free season at 187 days, and the season without a hard freeze (28°F) at 211 days.
A hard freeze (28°F) comes after April 6 in half of springs and before November 3 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts San Jon in zone 7a in ZIP code 88434, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, San Jon's NOAA station is in zone 7a: the coldest night of a typical year reaches 4°F (27 complete years).
Frost dates for every NOAA station in New Mexico · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00297867; 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 in San Jon?
In a normal year in San Jon, 90 days a year reach 90°F (17 of them 100°F or more), 100 nights fall to 32°F or colder and 51 days bring measurable precipitation.
- Days at 90°F or more
- 90a normal year
- Days at 100°F or more
- 17a normal year
- Nights at 32°F or colder
- 100a normal year
- Days that stay below freezing
- 5high of 32°F or less
- Days with 0.01 inch of precipitation
- 51a normal year
- Days with 1 inch of snow or more
- 6a normal year
The highest temperature in this station's record (since 1907) is 111°F, on July 13, 2016; the lowest is −20°F, on January 1, 1919.
The wettest calendar year on that record is 1941, with 34.76 in; the snowiest season is 1982–83, with 62.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00297867; records: ACIS (NOAA Regional Climate Centers), station USC00297867. Records use complete months only; a month missing more than three days is left out.
How sunny is San Jon?
Over a year 87% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around San Jon, 5.5 kWh per square metre a day. June is the sunniest month (90%) and December the cloudiest (82%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 84% | 3.2 |
| February | 83% | 4.1 |
| March | 84% | 5.4 |
| April | 86% | 6.7 |
| May | 87% | 7.5 |
| June | 90% | 7.9 |
| July | 90% | 7.5 |
| August | 89% | 6.7 |
| September | 89% | 5.8 |
| October | 86% | 4.5 |
| November | 86% | 3.5 |
| December | 82% | 2.8 |
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 Jon need?
A normal year in San Jon brings 3,503 heating degree days, 35% fewer than the median U.S. place (5,373), and 1,814 cooling degree days, 100% more than the median (908). Five months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 4,911 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 769 | 0 |
| February | 591 | 1 |
| March | 423 | 6 |
| April | 208 | 34 |
| May | 58 | 159 |
| June | 1 | 384 |
| July | 0 | 495 |
| August | 0 | 442 |
| September | 20 | 240 |
| October | 186 | 51 |
| November | 479 | 4 |
| December | 767 | 0 |
| Year (annual) | 3,503 | 1,814 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00297867. 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.
Has San Jon been warmer than normal lately?
Over 72 complete years from 1910 to 2018, the station's annual mean temperature rose at a fitted 1.0°F per century (+0.06°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does San Jon's climate compare?
San Jon is warmer than 79 of the other 97 places with their own NOAA record in New Mexico, and wetter than 78. Across the 7,247 U.S. stations with normals, its annual mean of 60.3°F is warmer than 76%.
In the Köppen classification computed from these normals, San Jon 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 Jon share this climate record?
Grady 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.
- Grady, NM83 people · 20 mi S
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 Jon's climate
What is the coldest month in San Jon?
January, with a normal high of 55°F and a normal low of 26°F. The warmest is July (95°F by day, 67°F at night).
Does it snow in San Jon?
Yes: 17 inches in a normal year, falling on 6 days with 0.1 inch or more, the most in December (5.4 inches).
What is the rainiest month in San Jon?
July, with 2.69 in of precipitation in a normal year; the driest is February with 0.43 in.
What plant hardiness zone is San Jon in?
The USDA's 2023 map puts San Jon in zone 7a in ZIP code 88434, the nearest ZIP area. By the same method at San Jon's NOAA station, the coldest night of a typical year reaches 4°F (27 years, 1991-2020): zone 7a.
How late can frost come in San Jon?
In half of years the last 32°F night comes after April 18; in one year in ten it comes after May 3. Waiting until May 3 leaves about a one-in-ten chance of a later frost.
Nearby and next
- New Mexico climateThe statewide normals and every place in the state
- Tucumcari, NM16 miles from this station, 59.1°F a year
- Ragland (3 mi SSW), NM33 miles from this station, 56.2°F a year
- McCarty Ranch, NM34 miles from this station, 56.5°F a year
- Bravo, TX40 miles from this station, 55.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made