San Martín, El Salvador Climate
The warmest month is March, with an average high of 35°C; the coldest is January, with an average low of 18°C. A normal year brings 1047 mm of precipitation.
Temperature through the year
The normal daily high and low. The line marks today.
- Normal low
- Normal high
- Reanalysis extreme high
- Reanalysis extreme low
Normals for Sep 24
- Normal high
- 27°C
- Normal low
- 20°C
- Reanalysis high
- 33°Cin 1994
- Reanalysis low
- 18°Cin 2016
- Chance of a wet day
- 85%
- Daylight
- 12 h 05 min
Month by month
Averages for 1991-2020. Wet days have at least 1 mm of precipitation in the reanalysis. Each month links to its own page.
| Month | Avg high | Avg low | Warmest | Coldest | Precipitation | Wet days |
|---|---|---|---|---|---|---|
| January | 31°C | 18°C | 37°C (2002) | 12°C (1996) | 9 mm | 3.1 |
| February | 33°C | 18°C | 38°C (1998) | 12°C (2006) | 8 mm | 2.8 |
| March | 35°C | 19°C | 39°C (1991) | 11°C (2009) | 6 mm | 3.1 |
| April | 35°C | 21°C | 40°C (1998) | 16°C (2014) | 27 mm | 6.0 |
| May | 32°C | 22°C | 41°C (1998) | 18°C (1998) | 130 mm | 18.6 |
| June | 29°C | 21°C | 36°C (1994) | 18°C (1993) | 174 mm | 24.0 |
| July | 30°C | 20°C | 38°C (1994) | 18°C (2008) | 136 mm | 21.7 |
| August | 30°C | 20°C | 37°C (2015) | 17°C (1999) | 167 mm | 21.7 |
| September | 28°C | 20°C | 37°C (1994) | 17°C (2007) | 189 mm | 24.0 |
| October | 28°C | 20°C | 35°C (1994) | 15°C (1999) | 146 mm | 18.6 |
| November | 29°C | 18°C | 35°C (1994) | 11°C (2006) | 39 mm | 9.0 |
| December | 30°C | 18°C | 35°C (2004) | 11°C (2010) | 16 mm | 3.1 |
| Year | 31°C | 20°C | 1047 mm | 156 |
Precipitation
Rain and melted snow together. The chance of a wet day is the share of days with at least 1 mm of precipitation in the reanalysis.
1047 mm in a normal year, most in September.
Chance of a wet day
- Chance of a wet day
Humidity and comfort
NASA POWER reanalysis, 1991-2020, for the grid cell around San Martín.
The muggiest month is September, when 94 percent of days are muggy or worse, with a mean dew point of 18°C or more.
| Month | Dew point | Humidity | Dry | Comfortable | Humid | Muggy | Oppressive | Miserable |
|---|---|---|---|---|---|---|---|---|
| January | 15°C | 62% | 18% | 52% | 30% | 1% | 0% | 0% |
| February | 14°C | 56% | 26% | 53% | 21% | 0% | 0% | 0% |
| March | 14°C | 54% | 23% | 47% | 28% | 3% | 0% | 0% |
| April | 17°C | 57% | 6% | 25% | 47% | 21% | 0% | 0% |
| May | 19°C | 69% | 1% | 5% | 28% | 58% | 8% | 0% |
| June | 20°C | 80% | 0% | 1% | 8% | 71% | 20% | 0% |
| July | 19°C | 76% | 0% | 2% | 17% | 75% | 6% | 0% |
| August | 20°C | 78% | 0% | 1% | 13% | 69% | 17% | 0% |
| September | 20°C | 84% | 0% | 0% | 5% | 74% | 20% | 0% |
| October | 20°C | 84% | 0% | 1% | 14% | 73% | 12% | 0% |
| November | 18°C | 76% | 2% | 11% | 42% | 43% | 1% | 0% |
| December | 16°C | 70% | 6% | 29% | 54% | 10% | 0% | 0% |
Comfort is judged by the day's mean dew point: dry below 13°C, comfortable to 16°C, humid to 18°C, muggy to 21°C, oppressive to 24°C, miserable above.
Clouds
Average share of the sky covered, from satellite (CERES and GEWEX SRB) by way of NASA POWER, 1991-2020.
The clearest month is March, with the sky 44 percent covered on average; the cloudiest is June, at 77 percent.
Wind
The mean wind speed over the whole day, from the MERRA-2 reanalysis by way of NASA POWER. Gusts run well above it.
The windiest month is January, averaging 12.2 km/h at 10 meters (33 feet) above the ground.
Daylight and sunshine
The longest day is Jun 16, with 12 h 57 min of daylight; the shortest is Dec 12, with 11 h 19 min.
- Day length
Solar energy
Average daily sunshine reaching the ground on a flat surface, in kilowatt-hours per square meter, clouds included.
Month pages
The weather in San Martín in each month, day by day.
What this means
A normal is the average of the thirty years 1991 to 2020, the period the World Meteorological Organization and NOAA use for comparison. It is an average, not a forecast: most days depart from it, and some by a long way.
Where no station record is within reach, the extremes shown are the highest and lowest the reanalysis produced for the date in 1991-2020, not measured records.
Cloud, humidity, wind and sunshine come from a reanalysis: a weather model run over the past with every observation fed in, averaged over a grid cell about 50 km across. It is consistent everywhere on Earth; it smooths local detail such as a lake shore or a valley.
More for this place
Nearby
Sources
Cloud, humidity, wind and sunshine, and temperature and precipitation: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.