Cupertino, California Weather
Coastal fog thickens at dawn. Day 76 of spring. Read this microseason across nine climate regions →
Cupertino weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Overcast——83°54°—
- ThursdayJun 4Clear——85°51°+2°
- FridayJun 5Clear——91°54°+6°
- SaturdayJun 6Overcast——78°55°-13°
- SundayJun 7Overcast——79°50°+1°
- MondayJun 8Overcast11%—80°53°+1°
- TuesdayJun 9Overcast——77°56°-3°
PM2.5/PM10 ratio 0.66 with 13 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 45 — peak already passed at 1 PM under clear skies. Levels should ease through evening.
- Present
- AQI 45
- UV peak
- 4.8 at earlier today
- Sky at peak
- clear
- Projected peak
- AQI 45
PM × Wind × Precip
PM2.5/PM10 ratio 0.66 with 13 mph wind — characteristic of long-range haze transport rather than a local source.
- PM2.5/PM10
- 0.66
- 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
- 5:54 AM
- Moonset
- 3:21 PM
- In sign
- ♑︎ Capricorn
Coastal fog thickens at dawn
Cupertino at a glance
- Today vs. normal: 5°F above the seasonal normal for this latitude
- Last frost: March 31 (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.