El Cajon, California Weather
Coastal fog thickens at dawn. Day 76 of spring. Read this microseason across nine climate regions →
El Cajon weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Foggy——78°61°—
- ThursdayJun 4Foggy——77°57°-1°
- FridayJun 5Foggy——80°57°+3°
- SaturdayJun 6Overcast——78°65°-2°
- SundayJun 7Overcast——76°63°-2°
- MondayJun 8Clear——77°62°+1°
- TuesdayJun 9Clear——80°64°+3°
Ozone at AQI 78 now. AQI flat over the last 6 hours (within ±3 points). With UV 10 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 106 by mid-afternoon.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
Ozone × UV × Sky
Ozone at AQI 78 now. With UV 10 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 106 by mid-afternoon.
- Present
- AQI 78
- UV peak
- 10.1 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 106
PM × Wind × Precip
PM2.5/PM10 ratio 0.67 with 9 mph wind — characteristic of long-range haze transport rather than a local source.
- PM2.5/PM10
- 0.67
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- transport
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
The higher the clouds, the finer the weather.
- Moonrise
- 5:18 AM
- Moonset
- 3:14 PM
- In sign
- ♑︎ Capricorn
Coastal fog thickens at dawn
El Cajon at a glance
- Today vs. normal: 4°F below the seasonal normal for this latitude
- Last frost: March 4 (climatological average for this latitude)
- Microseason: Jun 1–5
- Planting window: Harvest spring lettuce before it bolts. Sow heat-tolerant greens.
Right now in the garden
Peak growing season
As of June 3, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | — | — |
| March | lettuce, peas, spinach, radishes | — |
| April | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | — |
| May | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | — | tomatoes, beans, summer squash |
| August | — | tomatoes, beans, summer squash |
| September | — | tomatoes, beans, summer squash |
| October | fall brassicas, garlic (overwinter), carrots | winter squash, tomatoes (last) |
| November | fall brassicas, garlic (overwinter), carrots | — |
| December | — | — |
A year in weather
August is El Cajon's warmest month, with a mean near 74°F, and December is its coldest at about 56°F. Rainfall peaks in February at 2.6 inches and falls to a low of 0.0 inches in August.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 57° | 2.3″ | 3 |
| February | 57° | 2.6″ | 4 |
| March | 59° | 1.6″ | 3 |
| April | 62° | 0.8″ | 2 |
| May | 64° | 0.3″ | 1 |
| June | 67° | 0.1″ | 0 |
| July | 72° | 0.1″ | 0 |
| August | 74° | 0.0″ | 0 |
| September | 73° | 0.2″ | 0 |
| October | 68° | 0.5″ | 1 |
| November | 61° | 0.9″ | 2 |
| December | 56° | 1.6″ | 3 |
Regional context
El Cajon sits within a hot-summer Mediterranean climate region. Nearby cities in this cohort share comparable temperature ranges, seasonal patterns, and growing conditions.
Similar climates: Los Angeles, CA, San Francisco, CA, San Diego, CA, Riverside, CA, Sacramento, CA.
Naturalist notes
By late May, California toads begin calling from sandy washes and temporary pools after dusk, their trill a signal that water temperatures have risen enough for breeding.
Coastal prickly pear cactus starts blooming across the foothills. Its yellow flowers open in sequence, each lasting a single day, peaking for roughly three weeks.
Frequently asked
- When does it freeze in El Cajon?
- El Cajon's final spring frost usually arrives around mid-March, and the first fall frost appears near mid-December.
- What is the rainy season in El Cajon?
- February is the wettest month, averaging about 2.6 inches of rain, while the annual total reaches roughly 11 inches.
- What is the warmest month in El Cajon?
- August is normally the warmest month, averaging about 74°F.
- What is the coldest month in El Cajon?
- December is normally the coldest month, averaging about 56°F.
- When can I start a vegetable garden in El Cajon?
- Cool-season crops such as peas and lettuce can be sown near the date of the last spring frost in mid-March. Warm-season crops like tomatoes and peppers should wait until 1 to 2 weeks after that date.
- How many rainy days does El Cajon get?
- El Cajon averages about 20 rainy days per year.
- What hardiness zone is El Cajon?
- El Cajon's USDA hardiness zone is based on the lowest average winter temperature. A current zone designation can be found through the USDA's online lookup using the city ZIP code.
Climate
El Cajon, California falls within a hot-summer Mediterranean climate zone. January means stay close to 57°F, while July averages 72°F — a 15°F swing between the seasons.
The city receives about 11 inches of precipitation spread over roughly 20 rainy days during a typical year.
Latitude (32.8°N), nearby bodies of water, and local elevation set the rhythm. Together they influence the plant life, the timing of frost, and the day-to-day weather story.