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The temperatures in San Marcos in September are comfortable with low of 19°C and and high up to 28°C.
There shouldn't be any rainy days in in San Marcos during September. Having said that, the days are very hot in September so hanging out outside is more recomanded during the after noons and evening time.
Our weather forecast can give you a great sense of what weather to expect in San Marcos in September 2025.
If you’re planning to visit San Marcos in the near future, we highly recommend that you review the 14 day weather forecast for San Marcos before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 19° / 10° | 2 | 29 | 0 | 41 mm | Good | San Marcos in January |
| February | 19° / 10° | 2 | 26 | 0 | 46 mm | Good | San Marcos in February |
| March | 19° / 10° | 2 | 29 | 0 | 34 mm | Good | San Marcos in March |
| April | 21° / 11° | 0 | 30 | 0 | 15 mm | Good | San Marcos in April |
| May | 22° / 13° | 1 | 30 | 0 | 14 mm | Good | San Marcos in May |
| June | 25° / 15° | 0 | 30 | 0 | 3 mm | Perfect | San Marcos in June |
| July | 28° / 18° | 1 | 30 | 0 | 14 mm | Perfect | San Marcos in July |
| August | 29° / 19° | 1 | 30 | 0 | 10 mm | Good | San Marcos in August |
| September | 28° / 19° | 0 | 30 | 0 | 9 mm | Perfect | San Marcos in September |
| October | 25° / 16° | 0 | 31 | 0 | 11 mm | Perfect | San Marcos in October |
| November | 22° / 13° | 1 | 29 | 0 | 27 mm | Good | San Marcos in November |
| December | 18° / 10° | 3 | 28 | 0 | 49 mm | Good | San Marcos in December |