San Leandro, California Weather
Summer heat deepens across the valleys. Day 15 of summer. Read this microseason across nine climate regions →
San Leandro weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 5Foggy——68°55°—
- MondayJul 6Foggy——65°55°-3°
- TuesdayJul 7Foggy——69°55°+4°
- WednesdayJul 8Overcast——75°57°+6°
- ThursdayJul 9Clear——75°59°0°
- FridayJul 10Overcast——79°58°+4°
- SaturdayJul 11Overcast——82°63°+3°
AQI 36 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 8.1 µg/m³ (AQI 45) with a 0.72 fine-to-coarse ratio and 5 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
PM × Wind × Precip
PM2.5 at 8.1 µg/m³ (AQI 45) with a 0.72 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.72
- 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
- 11:27 PM
- Moonset
- 11:27 AM
- In sign
- ♓︎ Pisces
Summer heat deepens across the valleys
San Leandro at a glance
- Today vs. normal: 14°F below the seasonal normal for this latitude
- Last frost: April 2 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
ZIP codes: 94577, 94578, 94579
16-Day Forecast — San Leandro
- Sun68°55°0%
- Mon65°55°0%
- Tue69°55°1%
- Wed75°57°0%
- Thu75°59°0%
- Fri79°58°0%
- Sat82°63°0%
- Sun76°64°1%
- Mon86°67°3%
- Tue82°65°6%
- Wed79°63°1%
- Thu81°62°3%
- Fri84°65°0%
- Sat79°63°0%
- Sun76°62°3%
- Mon77°61°3%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near San Leandro
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 | — | — |
| April | lettuce, peas, spinach, radishes | — |
| May | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | tomatoes, peppers, beans, squash | tomatoes, beans, summer squash |
| August | — | tomatoes, beans, summer squash |
| September | fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| October | fall brassicas, garlic (overwinter), carrots | winter squash, tomatoes (last) |
| November | — | — |
| December | — | — |
A year in weather
San Leandro's warmest month is September (~67°F mean) and its coldest is December (~49°F). Rainfall peaks in January (3.6 inches) and bottoms out in July (0.0 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 49° | 3.6″ | 14 |
| February | 51° | 3.5″ | 12 |
| March | 53° | 2.8″ | 14 |
| April | 57° | 1.5″ | 9 |
| May | 62° | 0.6″ | 5 |
| June | 65° | 0.1″ | 2 |
| July | 67° | 0.0″ | 0 |
| August | 66° | 0.0″ | 1 |
| September | 67° | 0.1″ | 2 |
| October | 63° | 0.6″ | 4 |
| November | 55° | 2.2″ | 9 |
| December | 49° | 3.2″ | 12 |
Regional context
San Leandro's climate, from NOAA NCEI 1991-2020 station normals, pairs 49°F Januarys with 67°F Julys — a 18°F swing. About 18.1 inches of precipitation falls over roughly 85 days a year.
San Leandro's moisture rides winter storm tracks: January brings 3.6 inches over 13.7 wet days, while July sees only 0.0 inches across 0.3 days in the dry warm season. That cool-season-wet pattern aligns San Leandro with places like Ashland, CA, San Lorenzo, CA and Cherryland, CA.
Freezes are uncommon in San Leandro, where the coldest month averages 49°F; cool-season crops grow fall through spring. Summer heat in September (about 67°F) is the binding constraint, not cold. Across San Leandro, elevation and tree cover drive a 4-7°F spread in San Leandro's overnight lows.
Similar climates: Ashland, CA, San Lorenzo, CA, Cherryland, CA, Castro Valley, CA, Oakland, CA.
Naturalist notes
In late spring, valley oaks at this latitude are leafing out fully and their new leaves shift from pale green to leathery dark green by early May.
Barn swallows return to the East Bay in numbers by late April and can be seen skimming low over the San Leandro Creek corridor, hawking insects on warm afternoons.
Frequently asked
- When does it freeze in San Leandro?
- In San Leandro, expect the last spring frost near mid-April; San Leandro's first autumn frost comes around mid-November.
- What is the rainy season in San Leandro?
- January is the wettest month in San Leandro, about 3.6 inches on average; the year totals roughly 18 inches.
- What is the warmest month in San Leandro?
- On average September tops the year in San Leandro at about 67°F.
- What is the coldest month in San Leandro?
- The coldest stretch in San Leandro falls in December, around 49°F on average.
- When can I start a vegetable garden in San Leandro?
- In San Leandro, sow peas and hardy greens around mid-April; San Leandro's tomatoes and peppers wait two weeks more.
- How many rainy days does San Leandro get?
- Expect roughly 85 wet days a year in San Leandro.
- What hardiness zone is San Leandro?
- With December around 49°F, San Leandro's zone reflects that minimum — the USDA ZIP map confirms San Leandro's band.
- What is the 10-day forecast for San Leandro?
- San Leandro'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 San Leandro?
- See this week's day-by-day rain chances for San Leandro in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in San Leandro?
- Current conditions for San Leandro and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the San Leandro forecast updated?
- The San Leandro forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in San Leandro?
- Today's sunrise and sunset times for San Leandro 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 San Leandro?
- The next few days in San Leandro's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Climate
In San Leandro, California, the hot-summer Mediterranean climate runs from about 49°F in January to 67°F in July, a 18°F seasonal range.
Yearly precipitation in San Leandro totals around 18 inches, spread over about 85 days of rain or snow.
San Leandro's 18°F range, set by its 37.7°N position, drives frost timing and what thrives in San Leandro.
ZIP codes in San Leandro
- 94578
- 94579
- 94577
- 94622