Pasadena, California Weather
Coastal fog thickens at dawn. Day 77 of spring. Read this microseason across nine climate regions →
Pasadena weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Foggy——84°57°—
- ThursdayJun 4Foggy——87°55°+3°
- FridayJun 5Foggy——87°56°0°
- SaturdayJun 6Overcast——81°65°-6°
- SundayJun 7Clear——79°61°-2°
- MondayJun 8Overcast——82°61°+3°
- TuesdayJun 9Partly Cloudy——84°65°+2°
Ozone at AQI 500 — peak already passed at 1 PM under clear skies. AQI flat over the last 6 hours (within ±3 points). Levels should ease through evening.
AVOID OUTDOORS Avoid outdoor exertion. Keep windows closed; use HEPA filtration indoors if available.
What's driving it
Ozone × UV × Sky
Ozone at AQI 500 — peak already passed at 1 PM under clear skies. Levels should ease through evening.
- Present
- AQI 500
- UV peak
- 4.0 at earlier today
- Sky at peak
- clear
- Projected peak
- AQI 500
PM × Wind × Precip
PM2.5 at 23.6 µg/m³, PM10 at 32.7 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.72
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- background
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).
The higher the clouds, the finer the weather.
- Moonrise
- 5:27 AM
- Moonset
- 3:15 PM
- In sign
- ♑︎ Capricorn
Coastal fog thickens at dawn
Pasadena at a glance
- Today vs. normal: 80°F — typical for the season
- Last frost: March 12 (climatological average for this latitude)
- Microseason: Jun 1–5
- Planting window: Harvest spring lettuce before it bolts. Sow heat-tolerant greens.
Right now in the garden
Peak growing season
As of June 4, 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
August is Pasadena's warmest month, with a mean near 76°F, and December is its coldest, around 55°F. Rainfall peaks in February at 4.5 inches and drops to a low of 0.0 inches in August.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 56° | 3.6″ | 5 |
| February | 56° | 4.5″ | 5 |
| March | 59° | 2.8″ | 4 |
| April | 62° | 0.9″ | 2 |
| May | 65° | 0.4″ | 1 |
| June | 69° | 0.1″ | 0 |
| July | 74° | 0.0″ | 0 |
| August | 76° | 0.0″ | 0 |
| September | 74° | 0.1″ | 0 |
| October | 68° | 0.7″ | 1 |
| November | 60° | 0.8″ | 2 |
| December | 55° | 2.5″ | 4 |
Regional context
Pasadena belongs to a hot-summer Mediterranean climate region, a group that shares similar temperature ranges, seasonal patterns, and growing conditions with nearby cities.
Similar climates: Los Angeles, CA, San Francisco, CA, San Diego, CA, Riverside, CA, Sacramento, CA.
Naturalist notes
In late May, juvenile Bewick’s wrens fledge from nest boxes and cavity nests across the Arroyo Seco, their noisy begging calls audible in the cool morning air.
By June, the spent flower stalks of foothill penstemon have dried to a crisp, and seeds begin to rattle loose when brushed by a hiker’s pant leg on chaparral trails.
Frequently asked
- When does it freeze in Pasadena?
- Pasadena's last spring frost typically arrives around mid-March, and the first fall frost around mid-December.
- What is the rainy season in Pasadena?
- February is the wettest month, averaging about 4.5 inches of rain; the city receives roughly 17 inches annually.
- What is the warmest month in Pasadena?
- August is typically warmest, averaging about 76°F.
- What is the coldest month in Pasadena?
- December is typically coldest, averaging about 55°F.
- When can I start a vegetable garden in Pasadena?
- Cool-season crops like peas and lettuce can be sown around the last spring frost (mid-March); warm-season crops such as tomatoes and peppers wait until 1–2 weeks after that date.
- How many rainy days does Pasadena get?
- Pasadena averages about 24 rainy days per year.
- What hardiness zone is Pasadena?
- Pasadena's USDA hardiness zone reflects its lowest average winter temperature; consult the USDA's online tool with the city ZIP for the current zone designation.
Climate
Pasadena, California falls within a hot-summer Mediterranean climate zone. Average January temperatures hover around 56°F, while July averages 74°F — an 18°F seasonal swing.
Over the course of a year, Pasadena collects about 17 inches of precipitation, distributed across roughly 24 rainy days.
Latitude (34.2°N), distance to large bodies of water, and local elevation set the year’s rhythm. These factors shape the plant life, the timing of frost, and the day-to-day weather story.