San Marcos, California climate: NOAA's gridded normals for the city, beside the nearest station records
NOAA's gridded 1991-2020 normals put San Marcos's center at January lows of 45°F and July highs of 82°F, a yearly mean of 63.7°F and 12.3 inches of precipitation. No NOAA station keeps a record under the city's name. The nearest station record, Escondido (5 miles E, 600 ft), has January lows of 45°F and July highs of 87°F.
96,620 people (Census Bureau 2024). Distances and directions are from the city's center.
- Jan 67° 45°
- Feb 67° 46°
- Mar 68° 48°
- Apr 71° 50°
- May 73° 55°
- Jun 77° 58°
- Jul 82° 62°
- Aug 85° 63°
- Sep 83° 61°
- Oct 78° 56°
- Nov 73° 49°
- Dec 67° 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 San Marcos's center.
What is each month like in San Marcos?
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. | Escondido high | Escondido low |
|---|---|---|---|---|---|---|
| January | 67°F | 45°F | 56.2°F | 2.46 | 69°F | 45°F |
| February | 67°F | 46°F | 56.3°F | 2.81 | 69°F | 46°F |
| March | 68°F | 48°F | 58.1°F | 2.13 | 71°F | 49°F |
| April | 71°F | 50°F | 60.6°F | 0.83 | 74°F | 52°F |
| May | 73°F | 55°F | 63.8°F | 0.32 | 77°F | 56°F |
| June | 77°F | 58°F | 67.5°F | 0.06 | 82°F | 60°F |
| July | 82°F | 62°F | 72.1°F | 0.05 | 87°F | 64°F |
| August | 85°F | 63°F | 73.9°F | 0.02 | 89°F | 65°F |
| September | 83°F | 61°F | 72.2°F | 0.13 | 87°F | 63°F |
| October | 78°F | 56°F | 67.0°F | 0.61 | 81°F | 57°F |
| November | 73°F | 49°F | 60.8°F | 1.04 | 75°F | 49°F |
| December | 67°F | 44°F | 55.4°F | 1.89 | 68°F | 44°F |
In metric: a yearly mean of 17.6°C, January lows of 7°C, July highs of 28°C and 313 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 San Marcos 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 |
|---|---|---|---|---|---|---|---|---|
| EscondidoEscondido #2 | 5 mi E | 600 ft | 65.8°F | 45°F | 87°F | 14.5 | 0 | January 2 |
| CarlsbadCarlsbad Palomar Airport | 6 mi W | 328 ft | 62.5°F | 48°F | 74°F | 11.4 | – | – |
| Vista | 8 mi NW | 430 ft | 62.7°F | 46°F | 79°F | 13.4 | – | January 30 |
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 San Marcos?
NOAA's grid gives no snow, frost dates or records, so these come from the nearest station record, Escondido (5 miles E, 600 ft). It gets 0 inches of snow in a normal year. The last spring frost (32°F) comes after January 2 in half of years and the first autumn frost before December 30. Its record high is 115°F (2020) and its record low 13°F (1901), on the National Weather Service's long record for the area (kept since 1893).
The USDA's 2023 Plant Hardiness Zone Map puts San Marcos in zone 10a across its 3 ZIP code areas.
Over a year 87% of the sunlight that would reach the ground under clear skies gets through the clouds in the area (5.4 kWh per square metre a day, NASA POWER 2001-2020); August is the sunniest month (92%) and February the cloudiest (83%).
Escondido'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 San Marcos; the nearest record's month pages have them.
Source: NOAA NCEI 1991-2020 normals, station USC00042863; 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 San Marcos, ZIP code by ZIP code?
3 ZIP code areas lie wholly or partly in San Marcos. On NOAA's grid 92069 is the warmest (64.0°F a year) and 92078 the coolest (63.5°F), a spread of 0.5°F. 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 |
|---|---|---|---|---|---|---|---|---|
| 92069 | 10a | 64.0°F | 44°F | 85°F | 15.2 | Escondido (5 mi) | January 2 | December 30 |
| 92078 | 10a | 63.5°F | 45°F | 82°F | 12.8 | Escondido (5 mi) | January 2 | December 30 |
| 92096 | 10a | 63.9°F | 44°F | 84°F | 14.0 | Escondido (4 mi) | January 2 | December 30 |
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.