Rancho San Diego, California Weather
Summer heat deepens across the valleys. Day 15 of summer. Read this microseason across nine climate regions →
Rancho San Diego weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 5Foggy——87°63°—
- MondayJul 6Overcast——87°62°0°
- TuesdayJul 7Foggy——84°61°-3°
- WednesdayJul 8Clear——87°70°+3°
- ThursdayJul 9Clear——88°72°+1°
- FridayJul 10Partly Cloudy——89°73°+1°
- SaturdayJul 11Overcast——82°73°-7°
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) with a 0.70 fine-to-coarse ratio and 6 mph wind — combustion smoke trapped in calm air, not road dust.
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) with a 0.70 fine-to-coarse ratio and 6 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.70
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- stagnant smoke
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
Rancho San Diego at a glance
- Today vs. normal: 81°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.
16-Day Forecast — Rancho San Diego
- Sun87°63°0%
- Mon87°62°0%
- Tue84°61°0%
- Wed87°70°0%
- Thu88°72°0%
- Fri89°73°0%
- Sat82°73°1%
- Sun91°72°4%
- Mon93°75°15%
- Tue91°78°15%
- Wed93°79°7%
- Thu98°83°13%
- Fri99°83°19%
- Sat96°80°15%
- Sun93°80°14%
- Mon96°77°13%
Forecast data from Open-Meteo (CC BY 4.0).
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
Rancho San Diego peaks at about 74°F in August and bottoms near 55°F in January; February brings the heaviest rain (2.1 inches) and July the least (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
By the nearest station's NOAA NCEI 1991-2020 normals, Rancho San Diego sees 55°F Januarys and 73°F Julys, a 18°F range, plus around 11 inches of precipitation across 94 days.
Precipitation in Rancho San Diego peaks in the cool season: February averages 2.1 inches across 9.6 storm-fed days, while July bottoms out at 0.1 inches over just 3.0 rainy days. That groups Rancho San Diego with places like Casa de Oro-Mount Helix, CA, Granite Hills, CA and El Cajon, CA on the same cool-season storm track.
Rancho San Diego rarely sees a hard freeze — its coldest month sits near 55°F — so planting spans most of the calendar. Heat peaks in August around 74°F, which confines cool-season crops to the shoulders of summer. Across Rancho San Diego, elevation and tree cover drive a 4-7°F spread in Rancho San Diego's overnight lows.
Similar climates: Casa de Oro-Mount Helix, CA, Granite Hills, CA, El Cajon, CA, Spring Valley, CA, Crest, CA.
Frequently asked
- When does it freeze in Rancho San Diego?
- Rancho San Diego's last spring frost lands near mid-March, and in Rancho San Diego the first fall frost follows around mid-December.
- What is the rainy season in Rancho San Diego?
- Rancho San Diego sees its heaviest rain in February (around 2.1 inches), part of roughly 11 inches a year.
- What is the warmest month in Rancho San Diego?
- On average August tops the year in Rancho San Diego at about 74°F.
- What is the coldest month in Rancho San Diego?
- The coldest stretch in Rancho San Diego falls in January, around 55°F on average.
- When can I start a vegetable garden in Rancho San Diego?
- Around mid-March, start frost-hardy crops in Rancho San Diego; tomatoes and basil belong a fortnight later.
- How many rainy days does Rancho San Diego get?
- Rancho San Diego records around 94 days of measurable precipitation annually.
- What hardiness zone is Rancho San Diego?
- With January around 55°F, Rancho San Diego's zone reflects that minimum — the USDA ZIP map confirms Rancho San Diego's band.
- What is the 10-day forecast for Rancho San Diego?
- Rancho San Diego'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 Rancho San Diego?
- See this week's day-by-day rain chances for Rancho San Diego in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Rancho San Diego?
- Current conditions for Rancho San Diego and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Rancho San Diego forecast updated?
- The Rancho San Diego forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Rancho San Diego?
- Today's sunrise and sunset times for Rancho San Diego 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 Rancho San Diego?
- The next few days in Rancho San Diego's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Climate
In Rancho San Diego, California, the hot-summer Mediterranean climate runs from about 55°F in January to 73°F in July, a 18°F seasonal range.
In a typical year Rancho San Diego records about 11 inches of precipitation on around 94 days.
Rancho San Diego's 18°F range, set by its 32.8°N position, drives frost timing and what thrives in Rancho San Diego.
ZIP codes in Rancho San Diego
- 91941
- 92019