Hayward, California Weather
Coastal fog thickens at dawn. Day 77 of spring. Read this microseason across nine climate regions →
Hayward weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Foggy——74°54°—
- FridayJun 5Overcast——80°54°+6°
- SaturdayJun 6Overcast——65°54°-15°
- SundayJun 7Overcast——67°53°+2°
- MondayJun 8Heavy Drizzle—0.37″61°54°-6°
- TuesdayJun 9Heavy Drizzle16%0.14″63°55°+2°
- WednesdayJun 10Partly Cloudy——74°55°+11°
PM2.5 at 8.6 µg/m³, PM10 at 11.8 µg/m³ — typical background levels with no transport signature. AQI down 7 over the last 6 hours (steady decline since this morning).
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 38 now. With UV 9.9 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 50 by mid-afternoon.
- Present
- AQI 38
- UV peak
- 9.9 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 50
PM × Wind × Precip
PM2.5 at 8.6 µg/m³, PM10 at 11.8 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.73
- 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).
A summer fog for fair, a winter fog for rain.
- Moonrise
- 6:33 AM
- Moonset
- 4:22 PM
- In sign
- ♒︎ Aquarius
Coastal fog thickens at dawn
Hayward at a glance
- Today vs. normal: 4°F below the seasonal normal for this latitude
- Last frost: April 2 (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 | — | — |
| 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
September brings Hayward's peak warmth with average temperatures around 67°F, while December marks the coldest period at roughly 51°F. Rain follows a Mediterranean pattern, peaking in December with 3.2 inches and disappearing entirely in July at 0.0 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 51° | 2.9″ | 5 |
| February | 54° | 3.1″ | 7 |
| March | 56° | 2.4″ | 6 |
| April | 58° | 1.2″ | 3 |
| May | 61° | 0.6″ | 1 |
| June | 65° | 0.1″ | 0 |
| July | 66° | 0.0″ | 0 |
| August | 67° | 0.1″ | 0 |
| September | 67° | 0.1″ | 0 |
| October | 64° | 0.8″ | 2 |
| November | 56° | 1.5″ | 4 |
| December | 51° | 3.2″ | 6 |
Regional context
The city falls within a hot-summer Mediterranean climate region, sharing temperature ranges and seasonal rhythms with surrounding communities that experience similar growing conditions.
Similar climates: Los Angeles, CA, San Francisco, CA, San Diego, CA, Riverside, CA, Sacramento, CA.
Naturalist notes
Late May brings the arrival of migrating Black-chinned Hummingbirds to the region's gardens and wildflower patches.
California poppies reach their peak bloom in early June, carpeting hillsides with orange flowers before summer heat sets in.
Frequently asked
- When does it freeze in Hayward?
- Spring's final frost usually occurs around mid-April, while the first fall frost typically arrives in mid-November.
- What is the rainy season in Hayward?
- December receives the most rainfall at approximately 3.2 inches, contributing to the city's annual total of roughly 16 inches.
- What is the warmest month in Hayward?
- September records the highest average temperatures at about 67°F.
- What is the coldest month in Hayward?
- December sees the lowest average temperatures at approximately 51°F.
- When can I start a vegetable garden in Hayward?
- Cool-season vegetables like peas and lettuce can be planted around the last spring frost in mid-April, while heat-loving crops such as tomatoes and peppers should wait 1–2 weeks later.
- How many rainy days does Hayward get?
- The city experiences approximately 35 rainy days annually.
- What hardiness zone is Hayward?
- Check the USDA's online ZIP code lookup tool to find Hayward's current hardiness zone, which reflects the area's average minimum winter temperatures.
Climate
Hayward, California experiences a hot-summer Mediterranean climate. Winter temperatures in January hover near 51°F, while July averages 66°F — creating a moderate 15°F seasonal swing.
Annual precipitation totals around 16 inches, distributed across roughly 35 rainy days throughout the year.
Weather patterns here reflect the city's latitude at 37.6°N, along with nearby water bodies and local elevation. These factors determine growing seasons, frost timing, and daily weather conditions.