Pomona, California climate: Normal weather by month, frost dates and records
Pomona's normal year runs from 42°F December nights to 92°F August afternoons, with 14.5 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 18.3°C, December lows of 5°C, August highs of 34°C, 368 mm of precipitation a year.
- NOAA stationPomona/Fairplex
- Station IDUSC00047050
- Location34.08°N 117.77°W
- Elevation999 ft (305 m)
- From the center2 miles
- Population147,966
On October 14, the normal high in Pomona is 81°F and the normal low 54°F, and the chance of measurable rain or snow is 8%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Pomona.
- Jan 68° 43°
- Feb 67° 45°
- Mar 72° 47°
- Apr 76° 50°
- May 78° 54°
- Jun 84° 57°
- Jul 90° 62°
- Aug 92° 63°
- Sep 89° 60°
- Oct 81° 54°
- Nov 74° 47°
- Dec 67° 42°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Pomona each month?
August is the warmest month, with normal highs of 92°F; December the coldest, with normal lows of 42°F. The most precipitation falls in February (4.15 in), the least in July (0.00 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 68°F | 43°F | 55.5°F | 2.91 | 5 | <1 | 1 | 10 h 10 min |
| February | 67°F | 45°F | 55.9°F | 4.15 | 6 | <1 | <1 | 11 h |
| March | 72°F | 47°F | 59.5°F | 2.12 | 4 | 1 | <1 | 11 h 50 min |
| April | 76°F | 50°F | 62.7°F | 0.97 | 2 | 2 | <1 | 13 h |
| May | 78°F | 54°F | 66.2°F | 0.22 | 1 | 4 | <1 | 13 h 50 min |
| June | 84°F | 57°F | 70.8°F | 0.06 | <1 | 7 | <1 | 14 h 20 min |
| July | 90°F | 62°F | 76.3°F | 0.00 | <1 | 17 | <1 | 14 h 10 min |
| August | 92°F | 63°F | 77.5°F | 0.03 | <1 | 19 | <1 | 13 h 30 min |
| September | 89°F | 60°F | 74.6°F | 0.01 | <1 | 15 | <1 | 12 h 30 min |
| October | 81°F | 54°F | 67.2°F | 0.97 | 3 | 5 | <1 | 11 h 20 min |
| November | 74°F | 47°F | 60.2°F | 0.74 | 3 | <1 | <1 | 10 h 30 min |
| December | 67°F | 42°F | 54.2°F | 2.29 | 5 | <1 | 1 | 9 h 50 min |
| Year (annual) | 78°F | 52°F | 65.0°F | 14.47 | 31 | 71 | 3 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 20°C | 6°C | 13.1°C | 74 mm |
| February | 20°C | 7°C | 13.3°C | 105 mm |
| March | 22°C | 8°C | 15.3°C | 54 mm |
| April | 24°C | 10°C | 17.1°C | 25 mm |
| May | 26°C | 12°C | 19.0°C | 6 mm |
| June | 29°C | 14°C | 21.6°C | 2 mm |
| July | 32°C | 17°C | 24.6°C | 0 mm |
| August | 34°C | 17°C | 25.3°C | 1 mm |
| September | 32°C | 16°C | 23.7°C | 0 mm |
| October | 27°C | 12°C | 19.6°C | 25 mm |
| November | 23°C | 8°C | 15.7°C | 19 mm |
| December | 19°C | 5°C | 12.3°C | 58 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00047050; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Pomona?
Normal highs sit between 65°F and 85°F in January, February, March, April, May, June, October, November and December. Of those, June has the fewest days with rain (0).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00047050.
When is the last frost in Pomona?
In Pomona, the last spring frost (32°F) comes after January 8 in half of years and after February 18 in one year in ten; the first autumn frost comes before December 28 in half of years and before December 5 in one year in ten. A night at 32°F or colder comes at all in 65% of years here (NOAA).
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- January 81 year in 10 after February 18; 9 in 10 after December 14
- First autumn frost, half of years before
- December 281 year in 10 before December 5; 9 in 10 before February 2
NOAA puts the median frost-free season at 354 days, and the season without a hard freeze (28°F) at 365 days.
The USDA's 2023 Plant Hardiness Zone Map puts Pomona in zone 10a across its 3 ZIP code areas (10a in 91766, the largest).
Frost dates for every NOAA station in California · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00047050; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
What hardiness zone is each Pomona ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. Pomona's 3 ZIP code areas are all in zone 10a. Each ZIP's frost dates are in the frost tool.
Source: USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; ZIP areas in the place: Census Bureau 2020 ZCTA-to-place relationship file. A ZIP area counts when at least a tenth of its land (and 0.5 km²) lies in the place.
How hot and how cold does it get in Pomona?
In a normal year in Pomona, 71 days a year reach 90°F (11 of them 100°F or more), 3 nights fall to 32°F or colder and 31 days bring measurable precipitation.
- Days at 90°F or more
- 71a normal year
- Days at 100°F or more
- 11a normal year
- Nights at 32°F or colder
- 3a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 31a normal year
The highest temperature in this station's record (since 1893) is 117°F, on June 17, 1917; the lowest is 21°F, on January 7, 1913.
The wettest calendar year on that record is 1978, with 39.97 in.
Source: NOAA NCEI 1991-2020 annual normals, station USC00047050; records: ACIS (NOAA Regional Climate Centers), station USC00047050. Records use complete months only; a month missing more than three days is left out.
How sunny is Pomona?
Over a year 92% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Pomona, 5.8 kWh per square metre a day. August is the sunniest month (96%) and December the cloudiest (85%). Among the 459 U.S. places of 50,000 or more, that ranks tied 3rd (with 7 others) in sunshine.
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 85% | 3.3 |
| February | 85% | 4.2 |
| March | 89% | 5.7 |
| April | 90% | 6.9 |
| May | 92% | 7.8 |
| June | 96% | 8.4 |
| July | 94% | 7.9 |
| August | 96% | 7.4 |
| September | 95% | 6.3 |
| October | 93% | 4.9 |
| November | 90% | 3.6 |
| December | 85% | 2.9 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Pomona need?
A normal year in Pomona brings 1,457 heating degree days, 73% fewer than the median U.S. place (5,373), and 1,495 cooling degree days, 65% more than the median (908). One month needs 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 5,557 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 299 | 4 |
| February | 261 | 6 |
| March | 188 | 18 |
| April | 108 | 39 |
| May | 50 | 88 |
| June | 9 | 182 |
| July | 0 | 350 |
| August | 0 | 389 |
| September | 3 | 289 |
| October | 40 | 108 |
| November | 163 | 20 |
| December | 335 | 1 |
| Year (annual) | 1,457 | 1,495 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00047050. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
How does Pomona's climate compare?
Pomona is warmer than 178 of the other 218 places with their own NOAA record in California, and wetter than 99. Across the 7,247 U.S. stations with normals, its annual mean of 65.0°F is warmer than 88%.
In the Köppen classification computed from these normals, Pomona is Csa: temperate, dry-summer, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Pomona share this climate record?
15 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- West Covina, CAalso near: San Gabriel (11 mi, 66.0°F a year); Fullerton (13 mi, 66.2°F a year)106,920 people · 8 mi W
- Diamond Bar, CAalso near: Anaheim (10 mi, 67.7°F a year); Chino (11 mi, 66.1°F a year)52,292 people · 6 mi SW
- Glendora, CAalso near: Mount Wilson CBS (14 mi, 58.4°F a year); San Gabriel (15 mi, 66.0°F a year)50,101 people · 6 mi NW
- Covina, CA49,245 people · 7 mi W
- Azusa, CA48,383 people · 9 mi NW
- Montclair, CA37,650 people · 4 mi E
- Claremont, CA36,139 people · 4 mi NE
- San Dimas, CA33,226 people · 3 mi NW
- La Verne, CA30,192 people · 3 mi N
- Walnut, CA27,250 people · 6 mi SW
- Valinda, CA21,626 people · 10 mi W
- South San Jose Hills, CA17,451 people · 9 mi SW
- Vincent, CA15,151 people · 9 mi W
- Citrus, CA10,813 people · 8 mi W
- Charter Oak, CA9,414 people · 5 mi W
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Pomona's climate
What is the coldest month in Pomona?
December, with a normal high of 67°F and a normal low of 42°F. The warmest is August (92°F by day, 63°F at night).
Does it snow in Pomona?
Rarely: NOAA's normal is no measurable snow a year.
What is the rainiest month in Pomona?
February, with 4.15 in of precipitation in a normal year; the driest is July with 0.00 in.
What plant hardiness zone is Pomona in?
The USDA's 2023 map puts Pomona in zone 10a across its 3 ZIP code areas (10a in 91766, the largest).
How late can frost come in Pomona?
In half of years the last 32°F night comes after January 8; in one year in ten it comes after February 18. Waiting until February 18 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Pomona in OctoberThis month day by day, its records and recent years
- California climateThe statewide normals and every place in the state
- Ontario, CA10 miles from this station, 66.8°F a year
- Chino, CA11 miles from this station, 66.1°F a year
- Anaheim, CA16 miles from this station, 67.7°F a year
- Fullerton, CA19 miles from this station, 66.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made