El Capitan Dam, California climate: Climate normals at a NOAA weather station
El Capitan Dam's normal year runs from 41°F December nights to 97°F August afternoons, with 16.0 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 18.6°C, December lows of 5°C, August highs of 36°C, 407 mm of precipitation a year.
- NOAA stationEl Capitan Dam
- Station IDUSC00042709
- Location32.89°N 116.81°W
- Elevation600 ft (183 m)
On October 22, the normal high in El Capitan Dam is 87°F and the normal low 51°F, and the chance of measurable rain or snow is 8%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for El Capitan Dam.
- Jan 72° 41°
- Feb 72° 41°
- Mar 74° 43°
- Apr 79° 45°
- May 83° 51°
- Jun 90° 50°
- Jul 95° 56°
- Aug 97° 58°
- Sep 94° 55°
- Oct 88° 51°
- Nov 79° 45°
- Dec 72° 41°
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 El Capitan Dam each month?
August is the warmest month, with normal highs of 97°F; December the coldest, with normal lows of 41°F. The most precipitation falls in February (3.62 in), the least in June (0.06 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 72°F | 41°F | 56.5°F | 3.16 | 7 | <1 | 5 | 10 h 10 min |
| February | 72°F | 41°F | 56.5°F | 3.62 | 8 | 1 | 3 | 11 h |
| March | 74°F | 43°F | 58.5°F | 2.77 | 7 | 2 | 3 | 12 h |
| April | 79°F | 45°F | 61.9°F | 1.34 | 5 | 4 | 2 | 13 h |
| May | 83°F | 51°F | 67.0°F | 0.54 | 3 | 6 | 1 | 13 h 50 min |
| June | 90°F | 50°F | 69.6°F | 0.06 | <1 | 16 | <1 | 14 h 20 min |
| July | 95°F | 56°F | 75.8°F | 0.09 | 1 | 25 | <1 | 14 h 10 min |
| August | 97°F | 58°F | 77.4°F | 0.13 | <1 | 28 | <1 | 13 h 20 min |
| September | 94°F | 55°F | 74.5°F | 0.13 | 1 | 23 | <1 | 12 h 30 min |
| October | 88°F | 51°F | 69.6°F | 0.84 | 2 | 13 | <1 | 11 h 30 min |
| November | 79°F | 45°F | 61.8°F | 1.03 | 4 | 4 | 2 | 10 h 30 min |
| December | 72°F | 41°F | 56.1°F | 2.33 | 7 | <1 | 5 | 10 h |
| Year (annual) | 83°F | 48°F | 65.4°F | 16.04 | 45 | 121 | 22 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 22°C | 5°C | 13.6°C | 80 mm |
| February | 22°C | 5°C | 13.6°C | 92 mm |
| March | 24°C | 6°C | 14.7°C | 70 mm |
| April | 26°C | 7°C | 16.6°C | 34 mm |
| May | 28°C | 11°C | 19.4°C | 14 mm |
| June | 32°C | 10°C | 20.9°C | 2 mm |
| July | 35°C | 14°C | 24.3°C | 2 mm |
| August | 36°C | 14°C | 25.2°C | 3 mm |
| September | 35°C | 13°C | 23.6°C | 3 mm |
| October | 31°C | 11°C | 20.9°C | 21 mm |
| November | 26°C | 7°C | 16.6°C | 26 mm |
| December | 22°C | 5°C | 13.4°C | 59 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00042709; 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 El Capitan Dam?
Normal highs sit between 65°F and 85°F in January, February, March, April, May, November and December. 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 USC00042709.
When is the last frost at El Capitan Dam?
In El Capitan Dam, the last spring frost (32°F) comes after March 19 in half of years and after June 1 in one year in ten; the first autumn frost comes before December 8 in half of years and before October 25 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
- March 191 year in 10 after June 1; 9 in 10 after December 31
- First autumn frost, half of years before
- December 81 year in 10 before October 25; 9 in 10 before January 15
NOAA puts the median frost-free season at 270 days, and the season without a hard freeze (28°F) at 333 days.
A hard freeze (28°F) comes after February 22 in half of springs and before January 1 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts El Capitan Dam in zone 10a in ZIP code 92021, the nearest ZIP area.
Frost dates for every NOAA station in California · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00042709; 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 at El Capitan Dam?
In a normal year in El Capitan Dam, 121 days a year reach 90°F (34 of them 100°F or more), 22 nights fall to 32°F or colder and 45 days bring measurable precipitation.
- Days at 90°F or more
- 121a normal year
- Days at 100°F or more
- 34a normal year
- Nights at 32°F or colder
- 22a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 45a normal year
The highest temperature in this station's record (since 1948) is 115°F, on June 27, 1990; the lowest is 22°F, on January 4, 1949.
The wettest calendar year on that record is 1978, with 31.17 in; the snowiest season is 1948–49, with 1.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00042709; records: ACIS (NOAA Regional Climate Centers), station USC00042709. Records use complete months only; a month missing more than three days is left out.
How sunny is it at El Capitan Dam?
Over a year 90% of the sunlight that would reach the ground under clear skies gets through the clouds at El Capitan Dam, 5.8 kWh per square metre a day. June is the sunniest month (94%) and February the cloudiest (83%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 85% | 3.5 |
| February | 83% | 4.3 |
| March | 87% | 5.7 |
| April | 89% | 7.0 |
| May | 90% | 7.7 |
| June | 94% | 8.3 |
| July | 92% | 7.7 |
| August | 94% | 7.3 |
| September | 93% | 6.3 |
| October | 91% | 5.0 |
| November | 88% | 3.8 |
| December | 84% | 3.1 |
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 El Capitan Dam record?
A normal year at El Capitan Dam brings 1,396 heating degree days, 74% fewer than the median U.S. place (5,373), and 1,572 cooling degree days, 73% more than the median (908). No month reaches 300 heating degree days. For gardens and crops, NOAA counts 5,704 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 270 | 5 |
| February | 248 | 10 |
| March | 218 | 17 |
| April | 137 | 44 |
| May | 50 | 112 |
| June | 21 | 161 |
| July | 1 | 334 |
| August | 1 | 383 |
| September | 3 | 288 |
| October | 27 | 171 |
| November | 139 | 43 |
| December | 282 | 5 |
| Year (annual) | 1,396 | 1,572 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00042709. 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 El Capitan Dam's climate compare?
El Capitan Dam is warmer than 188 of the 219 places with their own NOAA record in California, and wetter than 112. Across the 7,247 U.S. stations with normals, its annual mean of 65.4°F is warmer than 89%.
In the Köppen classification computed from these normals, El Capitan Dam is Csa: temperate, dry-summer, hot summer. 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.
Questions about El Capitan Dam's climate
What is the coldest month at El Capitan Dam?
December, with a normal high of 72°F and a normal low of 41°F. The warmest is August (97°F by day, 58°F at night).
Does it snow at El Capitan Dam?
Rarely: NOAA's normal is no measurable snow a year.
What is the rainiest month at El Capitan Dam?
February, with 3.62 in of precipitation in a normal year; the driest is June with 0.06 in.
What plant hardiness zone is El Capitan Dam in?
The USDA's 2023 map puts El Capitan Dam in zone 10a in ZIP code 92021, the nearest ZIP area.
How late can frost come at El Capitan Dam?
In half of years the last 32°F night comes after March 19; in one year in ten it comes after June 1. Waiting until June 1 leaves about a one-in-ten chance of a later frost.
Nearby and next
- California climateThe statewide normals and every place in the state
- Alpine, CA4 miles from this station, 62.6°F a year
- El Cajon, CA9 miles from this station, 65.2°F a year
- Ramona, CA12 miles from this station, 61.2°F a year
- Cuyamaca, CA15 miles from this station, 54.0°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made