San Luis Dam, California climate: Climate normals at a NOAA weather station
San Luis Dam's normal year runs from 39°F January nights to 93°F July afternoons, with 10.4 inches of precipitation and less than an inch of snow (0.1 in) a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 17.5°C, January lows of 4°C, July highs of 34°C, 265 mm of precipitation a year.
- NOAA stationSan Luis Dam
- Station IDUSC00047846
- Location37.05°N 121.06°W
- Elevation277 ft (84 m)
On October 24, the normal high in San Luis Dam is 76°F and the normal low 52°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 Dam.
- Jan 56° 39°
- Feb 62° 43°
- Mar 67° 47°
- Apr 73° 50°
- May 80° 56°
- Jun 88° 60°
- Jul 93° 65°
- Aug 93° 64°
- Sep 89° 61°
- Oct 79° 54°
- Nov 66° 45°
- Dec 57° 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 at San Luis Dam each month?
July is the warmest month, with normal highs of 93°F; January the coldest, with normal lows of 39°F. The most precipitation falls in January (2.20 in), the least in July (0.00 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 56°F | 39°F | 47.5°F | 2.20 | 12 | <1 | 6 | 9 h 50 min |
| February | 62°F | 43°F | 52.1°F | 2.00 | 11 | <1 | 1 | 10 h 50 min |
| March | 67°F | 47°F | 57.0°F | 1.63 | 8 | <1 | <1 | 11 h 50 min |
| April | 73°F | 50°F | 61.3°F | 0.51 | 5 | 1 | <1 | 13 h 10 min |
| May | 80°F | 56°F | 67.7°F | 0.74 | 3 | 5 | <1 | 14 h 10 min |
| June | 88°F | 60°F | 73.9°F | 0.15 | 1 | 11 | <1 | 14 h 40 min |
| July | 93°F | 65°F | 78.7°F | 0.00 | <1 | 20 | <1 | 14 h 30 min |
| August | 93°F | 64°F | 78.4°F | 0.02 | <1 | 21 | <1 | 13 h 40 min |
| September | 89°F | 61°F | 75.0°F | 0.02 | <1 | 14 | <1 | 12 h 30 min |
| October | 79°F | 54°F | 66.6°F | 0.48 | 3 | 3 | <1 | 11 h 20 min |
| November | 66°F | 45°F | 55.4°F | 1.03 | 7 | <1 | 1 | 10 h 10 min |
| December | 57°F | 39°F | 47.9°F | 1.67 | 10 | <1 | 5 | 9 h 40 min |
| Year (annual) | 75°F | 52°F | 63.5°F | 10.45 | 60 | 76 | 12 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 14°C | 4°C | 8.6°C | 56 mm |
| February | 17°C | 6°C | 11.2°C | 51 mm |
| March | 19°C | 8°C | 13.9°C | 41 mm |
| April | 23°C | 10°C | 16.3°C | 13 mm |
| May | 27°C | 13°C | 19.8°C | 19 mm |
| June | 31°C | 16°C | 23.3°C | 4 mm |
| July | 34°C | 18°C | 25.9°C | 0 mm |
| August | 34°C | 18°C | 25.8°C | 1 mm |
| September | 32°C | 16°C | 23.9°C | 1 mm |
| October | 26°C | 12°C | 19.2°C | 12 mm |
| November | 19°C | 7°C | 13.0°C | 26 mm |
| December | 14°C | 4°C | 8.8°C | 42 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00047846; 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 San Luis Dam?
Normal highs sit between 65°F and 85°F in March, April, May, October and November. Of those, October 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 USC00047846.
When is the last frost at San Luis Dam?
In San Luis Dam, the last spring frost (32°F) comes after January 27 in half of years and after February 22 in one year in ten; the first autumn frost comes before December 11 in half of years and before November 25 in one year in ten. A night at 32°F or colder comes at all in 95% of years here (NOAA).
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- January 271 year in 10 after February 22; 9 in 10 after December 31
- First autumn frost, half of years before
- December 111 year in 10 before November 25; 9 in 10 before January 6
NOAA puts the median frost-free season at 323 days, and the season without a hard freeze (28°F) at 359 days.
A hard freeze (28°F) comes after January 6 in half of springs and before December 24 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts San Luis Dam in zone 9b in ZIP code 95322, 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 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 USC00047846; 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 San Luis Dam?
In a normal year in San Luis Dam, 76 days a year reach 90°F (13 of them 100°F or more), 12 nights fall to 32°F or colder and 60 days bring measurable precipitation.
- Days at 90°F or more
- 76a normal year
- Days at 100°F or more
- 13a normal year
- Nights at 32°F or colder
- 12a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 60a normal year
The highest temperature in this station's record (since 1963) is 110°F, on July 26, 2006; the lowest is 14°F, on December 22, 1990.
The wettest calendar year on that record is 1998, with 25.06 in; the snowiest season is 2000–01, with 1.2 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00047846; records: ACIS (NOAA Regional Climate Centers), station USC00047846. Records use complete months only; a month missing more than three days is left out.
How sunny is it at San Luis Dam?
Over a year 89% of the sunlight that would reach the ground under clear skies gets through the clouds at San Luis Dam, 5.3 kWh per square metre a day. July is the sunniest month (97%) and January the cloudiest (74%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 74% | 2.4 |
| February | 78% | 3.5 |
| March | 81% | 4.8 |
| April | 85% | 6.2 |
| May | 90% | 7.5 |
| June | 95% | 8.3 |
| July | 97% | 8.2 |
| August | 97% | 7.4 |
| September | 95% | 6.0 |
| October | 91% | 4.4 |
| November | 83% | 2.9 |
| December | 74% | 2.2 |
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 San Luis Dam record?
A normal year at San Luis Dam brings 2,235 heating degree days, 58% fewer than the median U.S. place (5,373), and 1,696 cooling degree days, 87% 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 5,201 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 544 | 0 |
| February | 361 | 0 |
| March | 254 | 5 |
| April | 142 | 31 |
| May | 49 | 135 |
| June | 6 | 273 |
| July | 0 | 427 |
| August | 0 | 417 |
| September | 2 | 303 |
| October | 54 | 103 |
| November | 292 | 3 |
| December | 530 | 0 |
| Year (annual) | 2,235 | 1,696 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00047846. 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 Dam's climate compare?
San Luis Dam is warmer than 161 of the 219 places with their own NOAA record in California, and wetter than 45. Across the 7,247 U.S. stations with normals, its annual mean of 63.5°F is warmer than 84%.
In the Köppen classification computed from these normals, San Luis 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 San Luis Dam share this climate record?
Santa Nella 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.
- Santa Nella, CA1,686 people · 4 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 San Luis Dam's climate
What is the coldest month at San Luis Dam?
January, with a normal high of 56°F and a normal low of 39°F. The warmest is July (93°F by day, 65°F at night).
Does it snow at San Luis Dam?
Rarely: NOAA's normal is 0.1 inch a year.
What is the rainiest month at San Luis Dam?
January, with 2.20 in of precipitation in a normal year; the driest is July with 0.00 in.
What plant hardiness zone is San Luis Dam in?
The USDA's 2023 map puts San Luis Dam in zone 9b in ZIP code 95322, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 28°F (15 years, 1991-2020): zone 9b.
How late can frost come at San Luis Dam?
In half of years the last 32°F night comes after January 27; in one year in ten it comes after February 22. Waiting until February 22 leaves about a one-in-ten chance of a later frost.
Nearby and next
- California climateThe statewide normals and every place in the state
- Los Banos, CA11 miles from this station, 63.4°F a year
- Newman, CA16 miles from this station, 65.0°F a year
- Hollister, CA25 miles from this station, 58.6°F a year
- Gilroy, CA28 miles from this station, 60.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made