Brentwood, California climate: NOAA's gridded normals for the city, beside the nearest station records
NOAA's gridded 1991-2020 normals put Brentwood's center at January lows of 40°F and July highs of 90°F, a yearly mean of 61.8°F and 14.2 inches of precipitation. No NOAA station keeps a record under the city's name. The nearest station record, Antioch (4 miles NW, 60 ft), has January lows of 40°F and July highs of 91°F.
66,286 people (Census Bureau 2024). Distances and directions are from the city's center.
- Jan 56° 40°
- Feb 62° 43°
- Mar 67° 45°
- Apr 72° 48°
- May 79° 52°
- Jun 86° 57°
- Jul 90° 59°
- Aug 90° 59°
- Sep 87° 57°
- Oct 78° 52°
- Nov 65° 45°
- Dec 57° 39°
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 Brentwood's center.
What is each month like in Brentwood?
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. | Antioch high | Antioch low |
|---|---|---|---|---|---|---|
| January | 56°F | 40°F | 48.0°F | 3.02 | 56°F | 40°F |
| February | 62°F | 43°F | 52.1°F | 2.59 | 61°F | 44°F |
| March | 67°F | 45°F | 56.0°F | 2.11 | 67°F | 47°F |
| April | 72°F | 48°F | 59.7°F | 1.04 | 72°F | 50°F |
| May | 79°F | 52°F | 65.5°F | 0.49 | 79°F | 54°F |
| June | 86°F | 57°F | 71.3°F | 0.10 | 86°F | 59°F |
| July | 90°F | 59°F | 74.6°F | 0.00 | 91°F | 61°F |
| August | 90°F | 59°F | 74.3°F | 0.01 | 90°F | 60°F |
| September | 87°F | 57°F | 71.9°F | 0.07 | 87°F | 59°F |
| October | 78°F | 52°F | 65.1°F | 0.66 | 78°F | 54°F |
| November | 65°F | 45°F | 54.9°F | 1.45 | 65°F | 46°F |
| December | 57°F | 39°F | 48.0°F | 2.66 | 56°F | 40°F |
In metric: a yearly mean of 16.6°C, January lows of 4°C, July highs of 32°C and 361 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 Brentwood 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 |
|---|---|---|---|---|---|---|---|---|
| AntiochAntioch Pumping Plant #3 | 4 mi NW | 60 ft | 62.5°F | 40°F | 91°F | 12.6 | 0 | January 12 |
| Mount Diablo Junction | 12 mi W | 2,170 ft | 58.4°F | 42°F | 83°F | 26.1 | 1 | March 8 |
| LivermoreLivermore Municipal Airport | 18 mi S | 393 ft | 59.8°F | 38°F | 88°F | 15.2 | – | February 27 |
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 Brentwood?
NOAA's grid gives no snow, frost dates or records, so these come from the nearest station record, Antioch (4 miles NW, 60 ft). It gets 0 inches of snow in a normal year. The last spring frost (32°F) comes after January 12 in half of years and the first autumn frost before December 19. Its record high is 117°F (1961) and its record low 18°F (1972) (kept since 1955).
The USDA's 2023 Plant Hardiness Zone Map puts Brentwood in zone 9b (ZIP code 94513).
Over a year 89% of the sunlight that would reach the ground under clear skies gets through the clouds in the area (5.3 kWh per square metre a day, NASA POWER 2001-2020); July is the sunniest month (97%) and January the cloudiest (74%).
Antioch'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 Brentwood; the nearest record's month pages have them.
Source: NOAA NCEI 1991-2020 normals, station USC00040232; 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 Brentwood, ZIP code by ZIP code?
One ZIP code area lies wholly or partly in Brentwood. Each row also names the nearest station record and its frost dates.
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.