Weather in Rancho San Diego, California
Fog and sun in daily rhythm. Day 59 of spring. Read this microseason across nine climate regions →
- TodayMay 16Light Drizzle—71°61°
- SundayMay 17Overcast—70°57°
- MondayMay 18Overcast—74°51°
- TuesdayMay 19Overcast—77°61°
- WednesdayMay 20Overcast—79°63°
- ThursdayMay 21Overcast—77°63°
- FridayMay 22Clear—76°63°
- PM 2.5
- 12.2 μg/m³
- PM 10
- 21.5 μg/m³
- NO₂
- 2.1 μg/m³
- Ozone
- 102.0 μg/m³
- UV Index
- 0.5 Low
When the dew is on the grass, rain will never come to pass.
- Moonrise
- 1:05 PM
- Moonset
- 3:08 AM
- In sign
- ♉︎ Taurus
Fog and sun in daily rhythm
Rancho San Diego at a glance
- Today vs. normal: 13°F below the seasonal normal for this latitude
- Last frost: March 4 (climatological average for this latitude)
- Microseason: 28 of 72, May 16–20
- Planting window: Direct sow okra, melons, and southern peas. Thin carrot rows.
Right now in the garden
Peak growing season
As of May 17, 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
Rancho San Diego's warmest month is August (~74°F mean) and its coldest is December (~56°F). Rainfall peaks in February (2.6 inches) and bottoms out in August (0.0 inches).
| 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
Rancho San Diego sits within a hot-summer Mediterranean climate region — a cohort that shares similar temperature ranges, seasonal patterns, and growing conditions across nearby cities.
Similar climates: Los Angeles, CA, San Francisco, CA, San Diego, CA, Riverside, CA, Sacramento, CA.
Frequently asked
- When does it freeze in Rancho San Diego?
- Rancho San Diego's last spring frost typically falls around mid-March, and the first fall frost arrives around mid-December.
- What is the rainy season in Rancho San Diego?
- February is the wettest month with about 2.6 inches of rain on average; the city receives roughly 11 inches annually.
- What is the warmest month in Rancho San Diego?
- August is typically warmest, averaging about 74°F.
- What is the coldest month in Rancho San Diego?
- December is typically coldest, averaging about 56°F.
- When can I start a vegetable garden in Rancho San Diego?
- Cool-season crops (peas, lettuce) can be sown around the last spring frost (mid-March); warm-season crops (tomatoes, peppers) wait until 1–2 weeks after.
- How many rainy days does Rancho San Diego get?
- Rancho San Diego averages about 20 rainy days per year.
- What hardiness zone is Rancho San Diego?
- Rancho San Diego's USDA hardiness zone is determined by its lowest average winter temperature; check the USDA's online lookup with the city ZIP for the current zone designation.
Climate
Rancho San Diego, California sits in a hot-summer Mediterranean climate zone. January means hover near 57°F while July averages 72°F — a 15°F seasonal swing.
Across the year, Rancho San Diego receives about 11 inches of precipitation spread over roughly 20 rainy days.
The rhythm of the year is set by latitude (32.8°N), proximity to large water bodies, and elevation — all of which shape what grows here, when frost is likely, and what the weather story looks like day to day.