West Covina, California climate: NOAA's gridded normals for the city, beside the nearest station records
NOAA's gridded 1991-2020 normals put West Covina's center at January lows of 45°F and July highs of 89°F, a yearly mean of 65.6°F and 15.7 inches of precipitation. No NOAA station keeps a record under the city's name. The nearest station record, Pomona (8 miles E, 999 ft), has January lows of 43°F and July highs of 90°F.
106,920 people (Census Bureau 2024). Distances and directions are from the city's center.
- Jan 69° 45°
- Feb 69° 46°
- Mar 72° 48°
- Apr 75° 50°
- May 78° 55°
- Jun 83° 59°
- Jul 89° 63°
- Aug 91° 63°
- Sep 88° 61°
- Oct 82° 56°
- Nov 74° 49°
- Dec 68° 44°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
The months above are NOAA's gridded normals at West Covina's center.
What is each month like in West Covina?
NOAA's grid estimates the normals every 5 km or so from the stations around each point, terrain included. It smooths between stations, so night lows at the heart of a large city can run warmer than the grid shows: at five big-city airports we compared, the grid's highs were within about 1°F of the station and its lows 1-6°F cooler. The nearest record's high and low are beside each month.
| Month | High | Low | Mean | Precip. | Pomona high | Pomona low |
|---|---|---|---|---|---|---|
| January | 69°F | 45°F | 56.7°F | 3.65 | 68°F | 43°F |
| February | 69°F | 46°F | 57.4°F | 4.22 | 67°F | 45°F |
| March | 72°F | 48°F | 59.8°F | 2.42 | 72°F | 47°F |
| April | 75°F | 50°F | 62.8°F | 0.86 | 76°F | 50°F |
| May | 78°F | 55°F | 66.2°F | 0.35 | 78°F | 54°F |
| June | 83°F | 59°F | 71.0°F | 0.08 | 84°F | 57°F |
| July | 89°F | 63°F | 75.8°F | 0.03 | 90°F | 62°F |
| August | 91°F | 63°F | 76.8°F | 0.01 | 92°F | 63°F |
| September | 88°F | 61°F | 74.6°F | 0.12 | 89°F | 60°F |
| October | 82°F | 56°F | 68.6°F | 0.56 | 81°F | 54°F |
| November | 74°F | 49°F | 61.4°F | 0.94 | 74°F | 47°F |
| December | 68°F | 44°F | 55.8°F | 2.49 | 67°F | 42°F |
In metric: a yearly mean of 18.7°C, January lows of 7°C, July highs of 32°C and 400 mm of precipitation a year.
Source: NOAA NCEI U.S. Monthly Gridded Climate Normals 1991-2020 (nClimGrid, accession 0245564); NOAA NCEI 1991-2020 station normals. The grid cell holding the city's Census center point.
What do the station records around West Covina say?
Each row is a NOAA station's own 1991-2020 normals, with the snow and frost dates the grid does not give. A record downhill or nearer the coast than the city can run warmer, one uphill cooler: compare the elevations.
| Record | Where | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| PomonaPomona/Fairplex | 8 mi E | 999 ft | 65.0°F | 43°F | 90°F | 14.5 | 0 | January 8 |
| San GabrielSan Gabriel Fire Dept | 11 mi W | 363 ft | 66.0°F | 46°F | 86°F | 15.7 | 0 | January 4 |
| FullertonFullerton Municipal Airport | 13 mi S | 96 ft | 66.2°F | 46°F | 84°F | 11.9 | – | – |
Source: NOAA NCEI 1991-2020 U.S. Climate Normals; place center and population: Census Bureau 2024. Last frost: the median last spring date of 32°F.
How much snow, how late a frost, what zone and how much sun in West Covina?
NOAA's grid gives no snow, frost dates or records, so these come from the nearest station record, Pomona (8 miles E, 999 ft). It gets 0 inches of snow in a normal year. The last spring frost (32°F) comes after January 8 in half of years and the first autumn frost before December 28. Its record high is 117°F (1917) and its record low 21°F (1913) (kept since 1893).
The USDA's 2023 Plant Hardiness Zone Map puts West Covina in zone 10a across its 3 ZIP code areas.
Over a year 92% of the sunlight that would reach the ground under clear skies gets through the clouds in the area (5.8 kWh per square metre a day, NASA POWER 2001-2020); August is the sunniest month (96%) and December the cloudiest (85%).
Pomona's page has its months, frost probabilities, records by month and recent years. NOAA's grid has monthly figures only, so there are no day-by-day month pages for West Covina; the nearest record's month pages have them.
Source: NOAA NCEI 1991-2020 normals, station USC00047050; records: ACIS; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; sunshine: NASA POWER.
How does the climate vary across West Covina, ZIP code by ZIP code?
3 ZIP code areas lie wholly or partly in West Covina. On NOAA's grid 91790 is the warmest (65.8°F a year) and 91791 the coolest (65.6°F), so the city is nearly uniform. Each row also names the nearest station record and its frost dates.
| ZIP code | Zone | Year | Jan low | Jul high | Precip. | Nearest record | Last frost | First frost |
|---|---|---|---|---|---|---|---|---|
| 91790 | 10a | 65.8°F | 45°F | 89°F | 15.3 | San Gabriel (9 mi) | January 4 | January 2 |
| 91791 | 10a | 65.6°F | 45°F | 89°F | 15.7 | Pomona (7 mi) | January 8 | December 28 |
| 91792 | 10a | 65.8°F | 46°F | 88°F | 14.5 | Pomona (9 mi) | January 8 | December 28 |
Source: Census Bureau 2020 ZCTA-to-place relationship file and ZCTA centers; NOAA NCEI gridded and station normals, 1991-2020. A ZIP area counts when at least a tenth of its land (and 0.5 km²) is in the city; its figures are the grid cell at its center; frost dates are the nearest record's medians of 32°F.