Climate averages 1991–2020
San Marcos weather
in August.
A warm, very dry month: the warmest and the driest of the year. Meets the pleasant-weather rule
Long-term climate patterns, not a forecast for a particular trip.
August is a warm month in San Marcos: daytime highs average 26.9°C and nights cool to about 18.2°C. By daytime temperature it is the warmest month of the year.
Expect about 1.0 mm of rain on fewer than one day, which makes August a very dry month (the driest month of the year). Daylight, from sunrise to sunset, lasts about 13 h 23 min on an average August day.
The nearest other city in this atlas is Escondido (8 km away). In August its highs average 29.1°C, 2.2°C warmer than San Marcos, with 2.6 mm of rain.
Among the 498 cities listed in the United States, San Marcos ranks joint 384th of 498 for the warmest August highs and joint 51st of 498 for the driest August (rainfall, lowest first). The mean August high of those 498 cities is 29.9°C; San Marcos is 3.0°C cooler than that mean.
From August to September, average highs fall by 0.7°C to 26.2°C, and monthly rainfall rises from 1.0 mm to 3.9 mm.
The annual picture
August in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
San Marcos climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 16.8°C6.1°C | 6.1°C | 73 | 5.8 | 10.210 h |
| February | 16.7°C6.9°C | 6.9°C | 92 | 6.8 | 11.011 h |
| March | 17.6°C8.5°C | 8.5°C | 57 | 6.2 | 12.012 h |
| April | 19.1°C10.3°C | 10.3°C | 28 | 4.1 | 13.013 h |
| May | 20.7°C12.7°C | 12.7°C | 13 | 2.1 | 13.814 h |
| June | 23.2°C14.8°C | 14.8°C | 2.5 | 0.5 | 14.314 h |
| July | 25.8°C17.2°C | 17.2°C | 2.0 | 0.4 | 14.114 h |
| August, selected | 26.9°C18.2°C | 18.2°C | 1.0 | 0.2 | 13.413 h |
| September | 26.2°C17.3°C | 17.3°C | 3.9 | 0.7 | 12.412 h |
| October | 23.3°C13.7°C | 13.7°C | 17 | 2.6 | 11.411 h |
| November | 20.0°C9.4°C | 9.4°C | 28 | 3.5 | 10.510 h |
| December | 16.7°C6.2°C | 6.2°C | 54 | 5.1 | 10.010 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
August in nearby cities
- Escondido in AugustUnited States · 8 kmHigh 29.1°C · Low 18.8°C · 2.6 mm rain
- Vista in AugustUnited States · 10 kmHigh 28.9°C · Low 19.4°C · 1.0 mm rain
- Oceanside in AugustUnited States · 21 kmHigh 25.8°C · Low 19.1°C · 0.6 mm rain
- Temecula in AugustUnited States · 39 kmHigh 33.2°C · Low 19.5°C · 2.4 mm rain
- El Cajon in AugustUnited States · 43 kmHigh 28.3°C · Low 18.7°C · 1.8 mm rain
- Murrieta in AugustUnited States · 46 kmHigh 33.2°C · Low 20.1°C · 2.4 mm rain
- San Diego in AugustUnited States · 48 kmHigh 25.4°C · Low 18.0°C · 0.4 mm rain
- Chula Vista in AugustUnited States · 56 kmHigh 24.5°C · Low 18.1°C · 1.8 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for San Marcos) is explained once on the San Marcos year overview and on the Sources, method and limits page.
Vista lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.