El Cajon, California Weather
Summer heat deepens across the valleys. Day 15 of summer. Read this microseason across nine climate regions →
El Cajon weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 5Foggy——86°64°—
- MondayJul 6Mostly Clear——86°62°0°
- TuesdayJul 7Foggy——84°62°-2°
- WednesdayJul 8Clear——87°71°+3°
- ThursdayJul 9Clear——88°72°+1°
- FridayJul 10Partly Cloudy——89°73°+1°
- SaturdayJul 11Overcast——83°73°-6°
AQI 45 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 10.0 µg/m³ (AQI 53), ratio 0.70 with 7 mph wind — characteristic of long-range haze transport rather than a local source.
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 37 now. With UV 9.9 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 49 around 1 PM.
- Present
- AQI 37
- UV peak
- 9.9 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 49
PM × Wind × Precip
PM2.5 at 10.0 µg/m³ (AQI 53), ratio 0.70 with 7 mph wind — characteristic of long-range haze transport rather than a local source.
- PM2.5/PM10
- 0.70
- 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).








































If the first of July be rainy weather, 'twill rain more or less for four weeks together.
- Moonrise
- 11:03 PM
- Moonset
- 11:07 AM
- In sign
- ♓︎ Pisces
Summer heat deepens across the valleys
El Cajon at a glance
- Today vs. normal: 80°F — typical for the season
- Last frost: March 4 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
ZIP codes: 92019, 92020, 92021
16-Day Forecast — El Cajon
- Sun86°64°0%
- Mon86°62°0%
- Tue84°62°0%
- Wed87°71°0%
- Thu88°72°0%
- Fri89°73°0%
- Sat83°73°1%
- Sun91°72°4%
- Mon94°75°14%
- Tue91°78°15%
- Wed93°79°6%
- Thu98°83°13%
- Fri99°84°19%
- Sat96°80°15%
- Sun93°80°14%
- Mon96°77°13%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near El Cajon
Right now in the garden
Peak growing season
As of July 5, 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.
Microseason · July 1–5
Summer heat deepens across the valleys
Inland temperatures exceed 95°F regularly; fire danger reaches moderate to high across most of the region.
Day 186 of 365 · Wedge 37 of 72
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
The year in El Cajon tops out in August (~74°F) and dips lowest in January (~55°F), with February wettest at 2.1 inches and July driest at 0.1 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 55° | 2.0″ | 10 |
| February | 56° | 2.1″ | 10 |
| March | 58° | 1.9″ | 12 |
| April | 61° | 1.0″ | 10 |
| May | 64° | 0.3″ | 10 |
| June | 68° | 0.1″ | 8 |
| July | 73° | 0.1″ | 3 |
| August | 74° | 0.1″ | 4 |
| September | 73° | 0.1″ | 5 |
| October | 68° | 0.3″ | 6 |
| November | 61° | 1.0″ | 7 |
| December | 55° | 2.0″ | 9 |
Regional context
El Cajon swings from 55°F in January to 73°F in July (18°F) per NOAA NCEI 1991-2020 normals; precipitation in El Cajon runs about 11 inches on roughly 94 measurable days.
Cool-season fronts carry El Cajon's rain: February logs 2.1 inches on 9.6 days, against July's 0.1 inches on 3.0 — winter does the heavy lifting in El Cajon. It is a winter-storm rhythm El Cajon shares with places like Bostonia, CA, Casa de Oro-Mount Helix, CA and Winter Gardens, CA.
Hard freezes are rare in El Cajon: the coldest month averages 55°F, so El Cajon's growing window runs most of the year. August is the hottest stretch near 74°F, pushing cool-season crops to the milder shoulder months. Across El Cajon, elevation and tree cover drive a 4-7°F spread in El Cajon's overnight lows.
Similar climates: Bostonia, CA, Casa de Oro-Mount Helix, CA, Winter Gardens, CA, Granite Hills, CA, Rancho San Diego, 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?
- Frost typically leaves El Cajon by mid-March and returns to El Cajon near mid-December.
- What is the rainy season in El Cajon?
- February is the wettest month in El Cajon, about 2.1 inches on average; the year totals roughly 11 inches.
- What is the warmest month in El Cajon?
- The warmest stretch in El Cajon comes in August, around 74°F on average.
- What is the coldest month in El Cajon?
- On average January is the chilliest month in El Cajon, about 55°F.
- When can I start a vegetable garden in El Cajon?
- El Cajon's last frost (mid-March) cues hardy greens; in El Cajon, hold heat-lovers two weeks past.
- How many rainy days does El Cajon get?
- El Cajon records around 94 days of measurable precipitation annually.
- What hardiness zone is El Cajon?
- El Cajon sits in the USDA zone set by January lows near 55°F; the USDA ZIP tool gives the band.
- What is the 10-day forecast for El Cajon?
- El Cajon's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
- Will it rain this week in El Cajon?
- See this week's day-by-day rain chances for El Cajon in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in El Cajon?
- Current conditions for El Cajon and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the El Cajon forecast updated?
- The El Cajon forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in El Cajon?
- Today's sunrise and sunset times for El Cajon are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter solstice.
- How accurate is the weather forecast for El Cajon?
- The next few days in El Cajon's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Climate
El Cajon, California has a hot-summer Mediterranean climate: January averages roughly 55°F, July about 73°F, 18°F between them.
Yearly precipitation in El Cajon totals around 11 inches, spread over about 94 days of rain or snow.
At 32.8°N, El Cajon's 18°F summer-to-winter swing sets when El Cajon's gardens wake and when frost returns.
ZIP codes in El Cajon
- 92020
- 92021
- 92019