Hillsborough, California Weather
Coastal fog thickens at dawn. Day 76 of spring. Read this microseason across nine climate regions →
Hillsborough weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Foggy——72°52°—
- ThursdayJun 4Clear——74°50°+2°
- FridayJun 5Clear——84°53°+10°
- SaturdayJun 6Overcast——65°54°-19°
- SundayJun 7Overcast——75°51°+10°
- MondayJun 8Overcast12%—70°52°-5°
- TuesdayJun 9Overcast——68°54°-2°
PM2.5/PM10 ratio 0.63 with 18 mph wind — characteristic of long-range haze transport rather than a local source. AQI flat over the last 6 hours (within ±3 points).
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 39 — peak already passed at 1 PM under clear skies. Levels should ease through evening.
- Present
- AQI 39
- UV peak
- 7.4 at earlier today
- Sky at peak
- clear
- Projected peak
- AQI 39
PM × Wind × Precip
PM2.5/PM10 ratio 0.63 with 18 mph wind — characteristic of long-range haze transport rather than a local source.
- PM2.5/PM10
- 0.63
- Wind
- breezy
- Recent rain
- 0h in last 6h
- Pattern
- transport
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
- 5:55 AM
- Moonset
- 3:22 PM
- In sign
- ♑︎ Capricorn
Coastal fog thickens at dawn
Hillsborough at a glance
- Today vs. normal: 7°F below the seasonal normal for this latitude
- Last frost: April 1 (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 3, 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.