San Jacinto, California climate: Normal weather by month, frost dates and records
San Jacinto's normal year runs from 39°F December nights to 97°F August afternoons, with 12.2 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 18.3°C, December lows of 4°C, August highs of 36°C, 310 mm of precipitation a year.
- NOAA stationSan Jacinto
- Station IDUSC00047813
- Location33.80°N 116.98°W
- Elevation1,525 ft (465 m)
- From the center1 miles
- Population55,515
On October 23, the normal high in San Jacinto is 80°F and the normal low 51°F, and the chance of measurable rain or snow is 7%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for San Jacinto.
- Jan 66° 40°
- Feb 66° 42°
- Mar 70° 45°
- Apr 74° 48°
- May 80° 53°
- Jun 89° 58°
- Jul 95° 64°
- Aug 97° 64°
- Sep 92° 61°
- Oct 82° 53°
- Nov 73° 44°
- Dec 65° 39°
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 Jacinto each month?
August is the warmest month, with normal highs of 97°F; December the coldest, with normal lows of 39°F. The most precipitation falls in February (2.76 in), the least in June (0.07 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 66°F | 40°F | 52.9°F | 2.66 | 6 | <1 | 4 | 10 h 10 min |
| February | 66°F | 42°F | 53.7°F | 2.76 | 6 | <1 | 2 | 11 h |
| March | 70°F | 45°F | 57.6°F | 1.69 | 5 | 1 | 1 | 11 h 50 min |
| April | 74°F | 48°F | 61.2°F | 0.79 | 3 | 3 | <1 | 13 h |
| May | 80°F | 53°F | 66.8°F | 0.47 | 2 | 8 | <1 | 13 h 50 min |
| June | 89°F | 58°F | 73.2°F | 0.07 | <1 | 17 | <1 | 14 h 20 min |
| July | 95°F | 64°F | 79.3°F | 0.20 | 1 | 27 | <1 | 14 h 10 min |
| August | 97°F | 64°F | 80.4°F | 0.12 | 1 | 29 | <1 | 13 h 30 min |
| September | 92°F | 61°F | 76.3°F | 0.26 | 1 | 22 | <1 | 12 h 30 min |
| October | 82°F | 53°F | 67.5°F | 0.54 | 2 | 10 | <1 | 11 h 20 min |
| November | 73°F | 44°F | 58.5°F | 0.77 | 3 | 2 | 1 | 10 h 30 min |
| December | 65°F | 39°F | 52.0°F | 1.87 | 5 | <1 | 7 | 10 h |
| Year (annual) | 79°F | 51°F | 65.0°F | 12.20 | 35 | 120 | 15 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 19°C | 5°C | 11.6°C | 68 mm |
| February | 19°C | 5°C | 12.1°C | 70 mm |
| March | 21°C | 7°C | 14.2°C | 43 mm |
| April | 24°C | 9°C | 16.2°C | 20 mm |
| May | 27°C | 12°C | 19.3°C | 12 mm |
| June | 32°C | 14°C | 22.9°C | 2 mm |
| July | 35°C | 18°C | 26.3°C | 5 mm |
| August | 36°C | 18°C | 26.9°C | 3 mm |
| September | 33°C | 16°C | 24.6°C | 7 mm |
| October | 28°C | 12°C | 19.7°C | 14 mm |
| November | 23°C | 7°C | 14.7°C | 20 mm |
| December | 18°C | 4°C | 11.1°C | 47 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00047813; 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 Jacinto?
Normal highs sit between 65°F and 85°F in January, February, March, April, May, October, November and December. Of those, October has the fewest days with rain (2).
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 USC00047813.
When is the last frost in San Jacinto?
In San Jacinto, the last spring frost (32°F) comes after January 31 in half of years and after February 28 in one year in ten; the first autumn frost comes before December 10 in half of years and before November 22 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
- January 311 year in 10 after February 28; 9 in 10 after December 31
- First autumn frost, half of years before
- December 101 year in 10 before November 22; 9 in 10 before January 6
NOAA puts the median frost-free season at 315 days, and the season without a hard freeze (28°F) at 359 days.
A hard freeze (28°F) comes after January 3 in half of springs and before December 21 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts San Jacinto in zone 9b across its 2 ZIP code areas (9b in 92582, the largest). By the map's own method, the average of each year's coldest night over 1991-2020, San Jacinto's NOAA station is in zone 9b: the coldest night of a typical year reaches 28°F (15 complete years).
Frost dates for every NOAA station in California · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00047813; 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.
What hardiness zone is each San Jacinto ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. San Jacinto's 2 ZIP code areas are all in zone 9b. Each ZIP's frost dates are in the frost tool.
Source: USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; ZIP areas in the place: Census Bureau 2020 ZCTA-to-place relationship file. A ZIP area counts when at least a tenth of its land (and 0.5 km²) lies in the place.
How hot and how cold does it get in San Jacinto?
In a normal year in San Jacinto, 120 days a year reach 90°F (39 of them 100°F or more), 15 nights fall to 32°F or colder and 35 days bring measurable precipitation.
- Days at 90°F or more
- 120a normal year
- Days at 100°F or more
- 39a normal year
- Nights at 32°F or colder
- 15a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 35a normal year
Source: NOAA NCEI 1991-2020 annual normals, station USC00047813.
How sunny is San Jacinto?
Over a year 91% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around San Jacinto, 5.8 kWh per square metre a day. June is the sunniest month (96%) and February the cloudiest (84%). Among the 459 U.S. places of 50,000 or more, that ranks tied 11th (with 9 others) in sunshine.
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 85% | 3.4 |
| February | 84% | 4.3 |
| March | 88% | 5.7 |
| April | 90% | 7.0 |
| May | 93% | 7.9 |
| June | 96% | 8.4 |
| July | 93% | 7.8 |
| August | 94% | 7.3 |
| September | 94% | 6.3 |
| October | 92% | 5.0 |
| November | 89% | 3.7 |
| December | 85% | 3.0 |
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 Jacinto need?
A normal year in San Jacinto brings 1,801 heating degree days, 66% fewer than the median U.S. place (5,373), and 1,810 cooling degree days, 99% more than the median (908). Three months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 5,606 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 374 | 0 |
| February | 316 | 1 |
| March | 238 | 9 |
| April | 145 | 30 |
| May | 57 | 115 |
| June | 7 | 252 |
| July | 0 | 445 |
| August | 0 | 477 |
| September | 3 | 340 |
| October | 47 | 124 |
| November | 211 | 17 |
| December | 403 | 0 |
| Year (annual) | 1,801 | 1,810 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00047813. 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 Jacinto been warmer than normal lately?
2025 averaged 67.0°F, 2.0°F above the 1991-2020 normal of 65.0°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 66.6°F | +1.6°F | 9.27 |
| 2022 | 67.3°F | +2.3°F | 5.09 |
| 2023 | 64.7°F | −0.3°F | 17.23 |
| 2024 | 66.6°F | +1.6°F | 11.32 |
| 2025 | 67.0°F | +2.0°F | 9.92 |
Source: observed years: ACIS, station USC00047813. A year counts only with all twelve months complete.
How does San Jacinto's climate compare?
San Jacinto is warmer than 178 of the other 218 places with their own NOAA record in California, and wetter than 67. Across the 7,247 U.S. stations with normals, its annual mean of 65.0°F is warmer than 88%.
In the Köppen classification computed from these normals, San Jacinto is BSh: hot 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 Jacinto share this climate record?
9 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.
- Beaumont, CAalso near: Hemet (10 mi, 66.3°F a year); Idyllwild Fire Dept (16 mi, 54.5°F a year)59,502 people · 6 mi N
- Banning, CA31,929 people · 11 mi NE
- Cherry Valley, CA7,302 people · 13 mi N
- Nuevo, CA6,737 people · 10 mi W
- Homeland, CA6,060 people · 9 mi SW
- Winchester, CA3,716 people · 8 mi SW
- Green Acres, CA3,226 people · 7 mi SW
- Romoland, CA2,430 people · 11 mi W
- Lakeview, CA2,177 people · 9 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 Jacinto's climate
What is the coldest month in San Jacinto?
December, with a normal high of 65°F and a normal low of 39°F. The warmest is August (97°F by day, 64°F at night).
Does it snow in San Jacinto?
Rarely: NOAA's normal is no measurable snow a year.
What is the rainiest month in San Jacinto?
February, with 2.76 in of precipitation in a normal year; the driest is June with 0.07 in.
What plant hardiness zone is San Jacinto in?
The USDA's 2023 map puts San Jacinto in zone 9b across its 2 ZIP code areas (9b in 92582, the largest). By the same method at San Jacinto's NOAA station, the coldest night of a typical year reaches 28°F (15 years, 1991-2020): zone 9b.
How late can frost come in San Jacinto?
In half of years the last 32°F night comes after January 31; in one year in ten it comes after February 28. Waiting until February 28 leaves about a one-in-ten chance of a later frost.
Nearby and next
- San Jacinto in OctoberThis month day by day, its records and recent years
- California climateThe statewide normals and every place in the state
- Hemet, CA6 miles from this station, 66.3°F a year
- Idyllwild Fire Dept, CA16 miles from this station, 54.5°F a year
- Redlands, CA21 miles from this station, 65.2°F a year
- Lake Elsinore, CA22 miles from this station, 66.0°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made