Granite Hills, California Weather
Summer heat deepens across the valleys. Day 15 of summer. Read this microseason across nine climate regions →
Granite Hills weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 5Foggy——87°63°—
- MondayJul 6Foggy——88°62°+1°
- TuesdayJul 7Foggy——87°61°-1°
- WednesdayJul 8Clear——90°66°+3°
- ThursdayJul 9Clear——92°68°+2°
- FridayJul 10Overcast——89°66°-3°
- SaturdayJul 11Overcast——86°66°-3°
AQI 45 (Good), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 10.0 µg/m³ (AQI 53) with a 0.70 fine-to-coarse ratio and 4 mph wind — combustion smoke trapped in calm air, not road dust.
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 37 now. With UV 9.9 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 49 around 1 PM.
- Present
- AQI 37
- UV peak
- 9.9 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 49
PM × Wind × Precip
PM2.5 at 10.0 µg/m³ (AQI 53) with a 0.70 fine-to-coarse ratio and 4 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.70
- Wind
- calm
- Recent rain
- 0h in last 6h
- Pattern
- stagnant smoke
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).
If the first of July be rainy weather, 'twill rain more or less for four weeks together.
- Moonrise
- 11:03 PM
- Moonset
- 11:07 AM
- In sign
- ♓︎ Pisces
Summer heat deepens across the valleys
Granite Hills at a glance
- Today vs. normal: 5°F below the seasonal normal for this latitude
- Last frost: March 4 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
16-Day Forecast — Granite Hills
- Sun87°63°0%
- Mon88°62°1%
- Tue87°61°0%
- Wed90°66°0%
- Thu92°68°0%
- Fri89°66°0%
- Sat86°66°1%
- Sun87°70°4%
- Mon87°73°16%
- Tue86°72°17%
- Wed93°74°7%
- Thu93°78°13%
- Fri103°82°19%
- Sat105°84°15%
- Sun93°80°14%
- Mon94°77°13%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of July 5, 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.
Microseason · July 1–5
Summer heat deepens across the valleys
Inland temperatures exceed 95°F regularly; fire danger reaches moderate to high across most of the region.
Day 186 of 365 · Wedge 37 of 72
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
The year in Granite Hills tops out in August (~74°F) and dips lowest in January (~55°F), with February wettest at 2.1 inches and July driest at 0.1 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 55° | 2.0″ | 10 |
| February | 56° | 2.1″ | 10 |
| March | 58° | 1.9″ | 12 |
| April | 61° | 1.0″ | 10 |
| May | 64° | 0.3″ | 10 |
| June | 68° | 0.1″ | 8 |
| July | 73° | 0.1″ | 3 |
| August | 74° | 0.1″ | 4 |
| September | 73° | 0.1″ | 5 |
| October | 68° | 0.3″ | 6 |
| November | 61° | 1.0″ | 7 |
| December | 55° | 2.0″ | 9 |
Regional context
In Granite Hills, NOAA NCEI 1991-2020 normals put January near 55°F and July near 73°F — a 18°F seasonal arc — with about 11 inches of precipitation over 94 rainy or snowy days.
Granite Hills's moisture rides winter storm tracks: February brings 2.1 inches over 9.6 wet days, while July sees only 0.1 inches across 3.0 days in the dry warm season. It is a winter-storm rhythm Granite Hills shares with places like Crest, CA, Winter Gardens, CA and Bostonia, CA.
With a coldest-month mean of 55°F, Granite Hills stays mostly frost-free and grows year-round. The August peak near 74°F is Granite Hills's real limit, pushing cool-season vegetables to spring and fall. Within Granite Hills, low or inland lots lose 3-5°F overnight versus Granite Hills's coastal ground.
Similar climates: Crest, CA, Winter Gardens, CA, Bostonia, CA, Rancho San Diego, CA, El Cajon, CA.
Frequently asked
- When does it freeze in Granite Hills?
- Granite Hills's last spring frost lands near mid-March, and in Granite Hills the first fall frost follows around mid-December.
- What is the rainy season in Granite Hills?
- February is the wettest month in Granite Hills, about 2.1 inches on average; the year totals roughly 11 inches.
- What is the warmest month in Granite Hills?
- The warmest stretch in Granite Hills comes in August, around 74°F on average.
- What is the coldest month in Granite Hills?
- On average January is the chilliest month in Granite Hills, about 55°F.
- When can I start a vegetable garden in Granite Hills?
- Time tomatoes in Granite Hills for two weeks after mid-March; peas and greens start at Granite Hills's frost line.
- How many rainy days does Granite Hills get?
- Granite Hills records around 94 days of measurable precipitation annually.
- What hardiness zone is Granite Hills?
- Granite Hills sits in the USDA zone set by January lows near 55°F; the USDA ZIP tool gives the band.
- What is the 10-day forecast for Granite Hills?
- Granite Hills's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
- Will it rain this week in Granite Hills?
- See this week's day-by-day rain chances for Granite Hills in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Granite Hills?
- Current conditions for Granite Hills and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Granite Hills forecast updated?
- The Granite Hills forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Granite Hills?
- Today's sunrise and sunset times for Granite Hills are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter solstice.
- How accurate is the weather forecast for Granite Hills?
- The next few days in Granite Hills's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Climate
Granite Hills, California occupies a hot-summer Mediterranean zone, with January means near 55°F and July around 73°F — a 18°F swing.
Rain and snow bring Granite Hills roughly 11 inches a year across approximately 94 measurable-precipitation days.
Latitude 32.8°N gives Granite Hills its 18°F swing, and with it the rhythm of Granite Hills's growing season.
ZIP codes in Granite Hills
- 92021
- 92019