Pomona, California Weather
Ceanothus blooms again. Day 93 of summer. Read this microseason across nine climate regions →
Pomona weather forecast — hour by hour, 7-day outlook, NOAA radar
Conditions updated 7:25 AM PDT · Open-Meteo
- TodaySep 21Overcast——80°64°—
- TuesdaySep 22Overcast——81°64°+1°
- WednesdaySep 23Clear——90°61°+9°
- ThursdaySep 24Clear——89°71°-1°
- FridaySep 25Partly Cloudy——92°72°+3°
- SaturdaySep 26Overcast——93°75°+1°
- SundaySep 27Partly Cloudy——89°74°-4°
Air quality now AQI 61 · Moderate
AQI 61 (Moderate), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 25.3 µg/m³ (AQI 81) with a 0.86 fine-to-coarse ratio and 1 mph wind — combustion smoke trapped in stagnant air, not road dust.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion during the projected peak around 8 PM.
What's driving it
PM × Wind × Precip
PM2.5 at 25.3 µg/m³ (AQI 81) with a 0.86 fine-to-coarse ratio and 1 mph wind — combustion smoke trapped in stagnant air, not road dust.
- PM2.5/PM10
- 0.86
- 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).
September dries up ditches or breaks down bridges.
- Moonrise
- 4:10 PM
- Moonset
- 1:35 AM
- In sign
- ♑︎ Capricorn
Ceanothus blooms again
Read this microseason across nine climate regions →
All 72 microseasons on the year wheel →
Pomona at a glance
- Today vs. normal: Today averages 72°F (high 80°F, low 64°F), about the 73°F normal for Sep 21
- Last frost: January 8 (1991–2020 median, NOAA station 3 km away)
- Microseason: Sep 21–25
- Planting calendar: September — plant tomatoes, peppers, beans, squash; harvest tomatoes, peppers, beans, summer squash, winter squash
16-Day Forecast — Pomona
- Mon80°64°1%
- Tue81°64°1%
- Wed90°61°0%
- Thu89°71°1%
- Fri92°72°2%
- Sat93°75°1%
- Sun89°74°1%
- Mon93°73°4%
- Tue97°78°5%
- Wed100°81°7%
- Thu104°86°5%
- Fri102°88°11%
- Sat100°85°10%
- Sun98°85°9%
- Mon98°84°7%
- Tue95°82°6%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near Pomona
Interactive wind and temperature map centered on Pomona — it loads in your browser. Open the full weather map.
Right now in the garden
Peak growing season
As of September 21, the growing season is at its peak — the first frost (around December 28) is weeks away. Fall transplants go in about 10–12 weeks before the first frost, October 5 to October 19 here. This city's planting calendar for September: plant tomatoes, peppers, beans, and squash; harvest tomatoes, peppers, beans, summer squash, and winter squash.
Sun & seasons in Pomona
Pomona sits in Los Angeles County, where the year’s longest day runs 14h 26m of daylight and its shortest just 9h 53m — a swing of +4h 33m between the June and December solstices. Clocks spring forward on Sunday, March 8, 2026 and fall back on Sunday, November 1, 2026.
Los Angeles, the state’s largest city, lies about 37 miles to the W. The nearest town Pomona tracks is Ontario, roughly 9 miles to the E.
Air quality in Pomona
Air quality in Pomona’s county has trended cleaner since 2020; its cleanest year on record was 2023 (median AQI 67). See the full air-quality history for Pomona.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | lettuce, peas, spinach, radishes | lettuce, spinach, radishes, fall brassicas, carrots |
| February | — | lettuce, peas, spinach, radishes |
| March | tomatoes, peppers, beans, squash | lettuce, peas, spinach |
| April | tomatoes, peppers, beans, squash | peas |
| May | beans, squash | beans, summer squash, garlic |
| June | beans, squash | tomatoes, peppers, beans, summer squash |
| July | beans, squash | tomatoes, peppers, beans, summer squash, winter squash |
| August | beans, squash | tomatoes, peppers, beans, summer squash, winter squash |
| September | tomatoes, peppers, beans, squash | tomatoes, peppers, beans, summer squash, winter squash |
| October | beans, squash, fall brassicas, carrots | beans, summer squash, winter squash |
| November | garlic (overwinter) | tomatoes, peppers, beans, summer squash, winter squash |
| December | lettuce, peas, spinach, radishes, garlic (overwinter) | tomatoes, peppers, beans, summer squash, winter squash, fall brassicas, carrots |
A year in weather
In Pomona, August runs warmest near 78°F and December coldest around 54°F, while February is the wettest month (4.2 inches) and July the driest (0.0 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 56° | 2.9″ | 5 |
| February | 56° | 4.2″ | 6 |
| March | 60° | 2.1″ | 4 |
| April | 63° | 1.0″ | 2 |
| May | 66° | 0.2″ | 1 |
| June | 71° | 0.1″ | 0 |
| July | 76° | 0.0″ | 0 |
| August | 78° | 0.0″ | 0 |
| September | 75° | 0.0″ | 0 |
| October | 67° | 1.0″ | 3 |
| November | 60° | 0.7″ | 3 |
| December | 54° | 2.3″ | 5 |
Regional context
Similar climates Montclair, CA, La Verne, CA, San Dimas, CA
Pomona swings from 56°F in January to 76°F in July (21°F) per NOAA NCEI 1991-2020 normals; precipitation in Pomona runs about 14.5 inches on roughly 31 measurable days.
Precipitation in Pomona peaks in the cool season: February averages 4.2 inches across 6.3 storm-fed days, while July bottoms out at 0.0 inches over just 0.2 rainy days. That cool-season-wet pattern aligns Pomona with places like Montclair, CA, La Verne, CA and San Dimas, CA.
Around January 8, Pomona sheds its freezing nights — lettuce, chard, arugula, and mustard greens go into Pomona's beds. Pomona's heat-lovers — tomatoes, peppers, squash — hold off until Pomona's frost risk clears, 10-14 days on. Frost returns to Pomona near December 28, ending the tender-crop season. Open lawns in Pomona whiten first when frost returns.
Similar climates: Montclair, CA, La Verne, CA, San Dimas, CA, Diamond Bar, CA, Claremont, CA.
Frequently asked
- When does it freeze in Pomona?
- Frost typically leaves Pomona by January 8 and returns to Pomona near December 28.
- What is the rainy season in Pomona?
- Rainfall in Pomona peaks in February near 4.2 inches, out of about 14 inches annually.
- What is the warmest month in Pomona?
- August is Pomona's warmest month, averaging about 78°F.
- What is the coldest month in Pomona?
- Pomona bottoms out in December, with a mean near 54°F.
- When can I start a vegetable garden in Pomona?
- Frost-hardy sowings begin at January 8 in Pomona; warm-season starts follow two weeks on.
- How many rainy days does Pomona get?
- Expect roughly 31 wet days a year in Pomona.
- What hardiness zone is Pomona?
- Pomona's hardiness zone tracks its winter low; with December near 54°F, check the USDA ZIP map for the exact zone.
- What is the 10-day forecast for Pomona?
- Pomona'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 Pomona?
- See this week's day-by-day rain chances for Pomona in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Pomona?
- Current conditions for Pomona and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Pomona forecast updated?
- The Pomona forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Pomona?
- Today's sunrise and sunset times for Pomona 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 Pomona?
- The next few days in Pomona's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Pomona sits at 34.1°N; its climate zone is hot-summer Mediterranean (Köppen approximation).
ZIP codes in Pomona
- 91766
- 91767
- 91768
- 91769