Weather in Acalanes Ridge, California
Fog and sun in daily rhythm. Day 59 of spring. Read this microseason across nine climate regions →
- TodayMay 16Partly Cloudy—76°53°
- SundayMay 17Overcast—73°50°
- MondayMay 18Partly Cloudy—82°52°
- TuesdayMay 19Partly Cloudy—88°54°
- WednesdayMay 20Overcast—88°54°
- ThursdayMay 21Overcast—83°51°
- FridayMay 22Overcast—74°51°
- PM 2.5
- 6.9 μg/m³
- PM 10
- 10.3 μg/m³
- NO₂
- 2.3 μg/m³
- Ozone
- 87.0 μg/m³
- UV Index
- 0.9 Low
When the dew is on the grass, rain will never come to pass.
- Moonrise
- 1:09 PM
- Moonset
- 3:47 AM
- In sign
- ♉︎ Taurus
Fog and sun in daily rhythm
Acalanes Ridge at a glance
- Today vs. normal: 72°F — typical for the season
- Last frost: April 3 (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
Warm-season window is open
As of May 17, the last spring frost has passed for most years. Transplant tomatoes, peppers, eggplants, basil, and cucurbits (cucumbers, squash, melons) now. Direct-sow beans and corn into warm soil.
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
Acalanes Ridge's warmest month is August (~74°F mean) and its coldest is January (~49°F). Rainfall peaks in January (3.2 inches) and bottoms out in July (0.0 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 49° | 3.2″ | 5 |
| February | 53° | 3.2″ | 6 |
| March | 57° | 2.3″ | 6 |
| April | 60° | 1.1″ | 3 |
| May | 65° | 0.5″ | 1 |
| June | 71° | 0.2″ | 0 |
| July | 73° | 0.0″ | 0 |
| August | 74° | 0.0″ | 0 |
| September | 72° | 0.1″ | 0 |
| October | 65° | 0.7″ | 1 |
| November | 56° | 1.6″ | 4 |
| December | 50° | 3.2″ | 6 |
Frequently asked
- When does it freeze in Acalanes Ridge?
- Acalanes Ridge's last spring frost typically falls around mid-April, and the first fall frost arrives around mid-November.
- What is the rainy season in Acalanes Ridge?
- January is the wettest month with about 3.2 inches of rain on average; the city receives roughly 16 inches annually.
- What is the warmest month in Acalanes Ridge?
- August is typically warmest, averaging about 74°F.
- What is the coldest month in Acalanes Ridge?
- January is typically coldest, averaging about 49°F.
- When can I start a vegetable garden in Acalanes Ridge?
- Cool-season crops (peas, lettuce) can be sown around the last spring frost (mid-April); warm-season crops (tomatoes, peppers) wait until 1–2 weeks after.
- How many rainy days does Acalanes Ridge get?
- Acalanes Ridge averages about 33 rainy days per year.
- What hardiness zone is Acalanes Ridge?
- Acalanes Ridge'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
Acalanes Ridge, California sits in a hot-summer Mediterranean climate zone. January means hover near 49°F while July averages 73°F — a 24°F seasonal swing.
Across the year, Acalanes Ridge receives about 16 inches of precipitation spread over roughly 33 rainy days.
The rhythm of the year is set by latitude (37.9°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.