| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 17.4° | 3.9° | 60.2mm | 6.6 | 78 |
| February | 19.5° | 5.9° | 40.3mm | 7.1 | 84 |
| March | 23.2° | 10° | 65mm | 8 | 84 |
| April | 26.9° | 13.8° | 77.6mm | 6.7 | 87 |
| May | 30.5° | 18.7° | 114.1mm | 7.8 | 70 |
| June | 34.1° | 22.3° | 82.1mm | 5.9 | 60 |
| July | 35.6° | 23.3° | 65.8mm | 5.6 | 54 |
| August | 36.4° | 23.2° | 62.8mm | 4.9 | 53 |
| September | 33° | 20.3° | 100.7mm | 6.6 | 63 |
| October | 28.2° | 14.7° | 113.6mm | 6.1 | 83 |
| November | 22.1° | 9.3° | 66.2mm | 6.3 | 87 |
| December | 18.2° | 5.2° | 47.1mm | 7.1 | 80 |
January in San Marcos averages a daily high of 17.4°C with nights around 3.9°C. Expect roughly 6.6 wet days totalling 60.2mm. Comfortable conditions for being outdoors all day.
February in San Marcos averages a daily high of 19.5°C with nights around 5.9°C. Expect roughly 7.1 wet days totalling 40.3mm. Comfortable conditions for being outdoors all day.
March in San Marcos averages a daily high of 23.2°C with nights around 10°C. Expect roughly 8 wet days totalling 65mm. Comfortable conditions for being outdoors all day.
April in San Marcos averages a daily high of 26.9°C with nights around 13.8°C. Expect roughly 6.7 wet days totalling 77.6mm. Comfortable conditions for being outdoors all day.
May in San Marcos averages a daily high of 30.5°C with nights around 18.7°C. Expect roughly 7.8 wet days totalling 114.1mm. Generally workable, with some weather to plan around.
June in San Marcos averages a daily high of 34.1°C with nights around 22.3°C. Expect roughly 5.9 wet days totalling 82.1mm. Generally workable, with some weather to plan around.
July in San Marcos averages a daily high of 35.6°C with nights around 23.3°C. Expect roughly 5.6 wet days totalling 65.8mm. Demanding conditions — pack for it and plan indoor options.
August in San Marcos averages a daily high of 36.4°C with nights around 23.2°C. Expect roughly 4.9 wet days totalling 62.8mm. Demanding conditions — pack for it and plan indoor options.
September in San Marcos averages a daily high of 33°C with nights around 20.3°C. Expect roughly 6.6 wet days totalling 100.7mm. Generally workable, with some weather to plan around.
October in San Marcos averages a daily high of 28.2°C with nights around 14.7°C. Expect roughly 6.1 wet days totalling 113.6mm. Comfortable conditions for being outdoors all day.
November in San Marcos averages a daily high of 22.1°C with nights around 9.3°C. Expect roughly 6.3 wet days totalling 66.2mm. Comfortable conditions for being outdoors all day.
December in San Marcos averages a daily high of 18.2°C with nights around 5.2°C. Expect roughly 7.1 wet days totalling 47.1mm. Comfortable conditions for being outdoors all day.
Each month scores out of 100. It starts at 100 and loses points for daytime highs outside a 20–27°C band, for wet days, and for nights below 2°C. Nothing else is weighted in — no crowd data, no prices, no opinion. San Marcos peaks at 87.
Based on 30 years of records, February–April scores highest for comfort in San Marcos, balancing daytime temperature against rainfall.
August is the warmest, averaging a daily high of 36.4°C.
May is the wettest, averaging 114.1mm of rain across roughly 7.8 wet days.
January is the coolest month, with average daily highs around 17.4°C.