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Climate and Average Weather Year Round in San Marcos El Salvador

In San Marcos, the wet season is oppressive and overcast, the dry season is humid and mostly clear, and it is warm year round. Over the course of the year, the temperature typically varies from 62°F to 85°F and is rarely below 58°F or above 89°F.

Based on the tourism score, the best time of year to visit San Marcos for warm-weather activities is from late November to late March.

Climate in San Marcos

warmhotwarmJanFebMarAprMayJunJulAugSepOctNovDecNowNow79%79%7%7%clearovercastprecipitation: 5.8 inprecipitation: 5.8 in0.1 in0.1 inmuggy: 99%muggy: 99%26%26%tourism score: 7.8tourism score: 7.84.14.1
San Marcos weather by month. Click on each chart for more information.

The temperature in San Marcos varies so little throughout the year that it is not entirely meaningful to discuss hot and cold seasons.

Average High and Low Temperature in San Marcos

Average High and Low Temperature in San MarcosJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F10°F10°F20°F20°F30°F30°F40°F40°F50°F50°F60°F60°F70°F70°F80°F80°F90°F90°F100°F100°FJan 1583°FJan 1583°FMar 3185°FMar 3185°F62°F62°F66°F66°FSep 481°FSep 481°FOct 2981°FOct 2981°F63°F63°F68°F68°F67°F67°F65°F65°FNowNow
The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.
AverageJanFebMarAprMayJunJulAugSepOctNovDec
High 83°F84°F85°F85°F83°F82°F83°F82°F81°F81°F82°F83°F
Temp. 71°F73°F74°F75°F74°F73°F73°F73°F72°F72°F72°F72°F
Low 63°F63°F65°F67°F68°F67°F67°F67°F67°F66°F64°F63°F

The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Average Hourly Temperature in San Marcos

Average Hourly Temperature in San MarcosJanFebMarAprMayJunJulAugSepOctNovDec12 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMNowNowcoolcoolcomfortablecomfortablewarm
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.

Mwanza, Tanzania (8,420 miles away) and Cimahi, Indonesia (11,220 miles) are the far-away foreign places with temperatures most similar to San Marcos (view comparison).

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In San Marcos, the average percentage of the sky covered by clouds experiences extreme seasonal variation over the course of the year.

The clearer part of the year in San Marcos begins around November 14 and lasts for 5.0 months, ending around April 15.

The clearest month of the year in San Marcos is January, during which on average the sky is clear, mostly clear, or partly cloudy 78% of the time.

The cloudier part of the year begins around April 15 and lasts for 7.0 months, ending around November 14.

The cloudiest month of the year in San Marcos is June, during which on average the sky is overcast or mostly cloudy 91% of the time.

Cloud Cover Categories in San Marcos

Cloud Cover Categories in San MarcosclearerclearercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Jan 1079%Jan 1079%Jun 47%Jun 47%Nov 1443%Nov 1443%Apr 1543%Apr 1543%NowNowclearmostly clearpartly cloudymostly cloudyovercast
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds.
FractionJanFebMarAprMayJunJulAugSepOctNovDec
Cloudier 22%24%31%57%85%91%85%85%88%80%55%30%
Clearer 78%76%69%43%15%9%15%15%12%20%45%70%

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in San Marcos varies significantly throughout the year.

The wetter season lasts 5.4 months, from May 13 to October 24, with a greater than 24% chance of a given day being a wet day. The month with the most wet days in San Marcos is September, with an average of 13.9 days with at least 0.04 inches of precipitation.

The drier season lasts 6.6 months, from October 24 to May 13. The month with the fewest wet days in San Marcos is January, with an average of 0.3 days with at least 0.04 inches of precipitation.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. The month with the most days of rain alone in San Marcos is September, with an average of 13.9 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 48% on September 11.

Daily Chance of Precipitation in San Marcos

Daily Chance of Precipitation in San MarcoswetdrydryJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Sep 1148%Sep 1148%Jan 81%Jan 81%May 1324%May 1324%Oct 2424%Oct 2424%NowNowrain
The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).
Days ofJanFebMarAprMayJunJulAugSepOctNovDec
Rain 0.3d0.3d0.6d2.2d8.3d12.9d11.5d12.9d13.9d9.8d2.8d1.1d

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. San Marcos experiences extreme seasonal variation in monthly rainfall.

The rainy period of the year lasts for 7.5 months, from April 11 to November 26, with a sliding 31-day rainfall of at least 0.5 inches. The month with the most rain in San Marcos is September, with an average rainfall of 5.8 inches.

The rainless period of the year lasts for 4.5 months, from November 26 to April 11. The month with the least rain in San Marcos is February, with an average rainfall of 0.1 inches.

Average Monthly Rainfall in San Marcos

The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average snowfall.
JanFebMarAprMayJunJulAugSepOctNovDec
Rainfall 0.1″0.1″0.1″0.6″3.3″5.4″4.3″4.9″5.8″4.1″1.0″0.2″

The length of the day in San Marcos varies over the course of the year. In 2024, the shortest day is December 21, with 11 hours, 19 minutes of daylight; the longest day is June 20, with 12 hours, 56 minutes of daylight.

Hours of Daylight and Twilight in San Marcos

Hours of Daylight and Twilight in San MarcosJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 6 minMar 1912 hr, 6 minMar 1912 hr, 56 minJun 2012 hr, 56 minJun 2012 hr, 7 minSep 2212 hr, 7 minSep 2211 hr, 19 minDec 2111 hr, 19 minDec 21nightnightdayNowNow
The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.
Hours ofJanFebMarAprMayJunJulAugSepOctNovDec
Daylight 11.4h11.7h12.1h12.4h12.8h12.9h12.8h12.6h12.2h11.8h11.5h11.3h

The earliest sunrise is at 5:28 AM on May 31, and the latest sunrise is 56 minutes later at 6:24 AM on January 24. The earliest sunset is at 5:25 PM on November 19, and the latest sunset is 1 hour, 3 minutes later at 6:28 PM on July 7.

Daylight saving time (DST) is not observed in San Marcos during 2024.

Sunrise & Sunset with Twilight in San Marcos

Sunrise & Sunset with Twilight in San MarcosJanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMMay 315:28 AMMay 315:28 AM6:28 PMJul 76:28 PMJul 7Nov 195:25 PMNov 195:25 PM6:24 AMJan 246:24 AMJan 24daynightnightSolarMidnightSolarMidnightSolarNoonSunriseSunsetNowNow
The solar day over the course of the year 2024. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray.

The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation.

Solar Elevation and Azimuth in San Marcos

Solar Elevation and Azimuth in San MarcosJanFebMarAprMayJunJulAugSepOctNovDec12 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AM0000101010102020202030303030404040405050505060606070708000001010101020202020303030304040404050505050606060707080805390NowNow
northeastsouthwest
Solar elevation and azimuth over the course of the year 2024. The black lines are lines of constant solar elevation (the angle of the sun above the horizon, in degrees). The background color fills indicate the azimuth (the compass bearing) of the sun. The lightly tinted areas at the boundaries of the cardinal compass points indicate the implied intermediate directions (northeast, southeast, southwest, and northwest).

The figure below presents a compact representation of key lunar data for 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases.

Moon Rise, Set & Phases in San Marcos

The time in which the moon is above the horizon (light blue area), with new moons (dark gray lines) and full moons (blue lines) indicated. The shaded overlays indicate night and civil twilight.

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

San Marcos experiences extreme seasonal variation in the perceived humidity.

The muggier period of the year lasts for 9.1 months, from March 8 to December 12, during which time the comfort level is muggy, oppressive, or miserable at least 44% of the time. The month with the most muggy days in San Marcos is August, with 30.3 days that are muggy or worse.

The month with the fewest muggy days in San Marcos is January, with 8.6 days that are muggy or worse.

Humidity Comfort Levels in San Marcos

Humidity Comfort Levels in San MarcosmuggyJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Jan 1526%Jan 1526%99%Sep 1799%Sep 17Mar 844%Mar 844%Dec 1244%Dec 1244%NowNowoppressiveoppressivemuggymuggyhumidhumidcomfortablecomfortabledrydry
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The percentage of time spent at various humidity comfort levels, categorized by dew point.
JanFebMarAprMayJunJulAugSepOctNovDec
Muggy days 8.6d9.6d16.1d23.2d29.1d29.2d29.6d30.3d29.6d27.3d19.0d12.8d

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in San Marcos experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 5.2 months, from November 3 to April 10, with average wind speeds of more than 7.2 miles per hour. The windiest month of the year in San Marcos is January, with an average hourly wind speed of 9.1 miles per hour.

The calmer time of year lasts for 6.8 months, from April 10 to November 3. The calmest month of the year in San Marcos is August, with an average hourly wind speed of 5.1 miles per hour.

Average Wind Speed in San Marcos

Average Wind Speed in San MarcoswindywindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph0 mph2 mph2 mph4 mph4 mph6 mph6 mph8 mph8 mph10 mph10 mph12 mph12 mph14 mph14 mph16 mph16 mphJan 139.3 mphJan 139.3 mphAug 185.1 mphAug 185.1 mphNov 37.2 mphNov 37.2 mphApr 107.2 mphApr 107.2 mphNowNow
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.
JanFebMarAprMayJunJulAugSepOctNovDec
Wind Speed (mph) 9.18.78.17.05.95.45.35.15.46.28.08.9

The predominant average hourly wind direction in San Marcos varies throughout the year.

The wind is most often from the south for 3.0 months, from March 27 to June 26 and for 2.1 months, from August 6 to October 10, with a peak percentage of 39% on June 3. The wind is most often from the east for 1.4 months, from June 26 to August 6, with a peak percentage of 38% on July 14. The wind is most often from the north for 5.5 months, from October 10 to March 27, with a peak percentage of 64% on January 1.

Wind Direction in San Marcos

Wind Direction in San MarcosNSESNJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%NowNowwestsoutheastnorth
northeastsouthwest
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

San Marcos is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.

The average water temperature does not vary significantly over the course of the year, remaining within 2°F of 84°F throughout.

Average Water Temperature in San Marcos

Average Water Temperature in San MarcosJanFebMarAprMayJunJulAugSepOctNovDec80°F80°F81°F81°F82°F82°F83°F83°F84°F84°F85°F85°F86°F86°F87°F87°F88°F88°FAug 786°FAug 786°F82°FJan 2582°FJan 25May 185°FMay 185°FSep 1085°FSep 1085°FDec 3183°FDec 3183°FMar 483°FMar 483°FNowNow
The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.
WaterJanFebMarAprMayJunJulAugSepOctNovDec
Temperature 82°F82°F83°F85°F85°F85°F86°F86°F85°F85°F84°F83°F

To characterize how pleasant the weather is in San Marcos throughout the year, we compute two travel scores.

The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit San Marcos for general outdoor tourist activities is from late November to late March, with a peak score in the second week of January.

Tourism Score in San Marcos

Tourism Score in San Marcosbest timeJanFebMarAprMayJunJulAugSepOctNovDec002244668810107.87.84.14.14.84.84.44.4NowNowtemperaturetemperature cloudscloudsprecipitationprecipitationtourism score
The tourism score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit San Marcos for hot-weather activities is from mid February to late April, with a peak score in the last week of March.

Beach/Pool Score in San Marcos

Beach/Pool Score in San Marcosbest timeJanFebMarAprMayJunJulAugSepOctNovDec002244668810106.26.23.93.95.45.4NowNowtemperaturetemperaturecloudscloudsprecipitationprecipitationbeach/pool score
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Methodology

For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.

Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.

Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.

Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.

Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

Temperatures in San Marcos are sufficiently warm year round that it is not entirely meaningful to discuss the growing season in these terms. We nevertheless include the chart below as an illustration of the distribution of temperatures experienced throughout the year.

Time Spent in Various Temperature Bands and the Growing Season in San Marcos

Time Spent in Various Temperature Bands and the Growing Season in San MarcosJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%100%Jan 1100%Jan 1100%Jul 2100%Jul 2NowNowcoolcomfortablewarmhot
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The percentage of time spent in various temperature bands. The black line is the percentage chance that a given day is within the growing season.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

Growing Degree Days in San Marcos

Growing Degree Days in San MarcosJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F1,000°F1,000°F2,000°F2,000°F3,000°F3,000°F4,000°F4,000°F5,000°F5,000°F6,000°F6,000°F7,000°F7,000°F8,000°F8,000°FJan 590°FJan 590°FMar 221,800°FMar 221,800°FDec 318,366°FDec 318,366°FNowNow
The average growing degree days accumulated over the course of the year, with 25th to 75th and 10th to 90th percentile bands.

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy experiences some seasonal variation over the course of the year.

The brighter period of the year lasts for 1.9 months, from February 14 to April 12, with an average daily incident shortwave energy per square meter above 6.4 kWh. The brightest month of the year in San Marcos is March, with an average of 6.9 kWh.

The darker period of the year lasts for 1.3 months, from May 15 to June 24, with an average daily incident shortwave energy per square meter below 5.0 kWh. The darkest month of the year in San Marcos is September, with an average of 4.6 kWh.

Average Daily Incident Shortwave Solar Energy in San Marcos

Average Daily Incident Shortwave Solar Energy in San MarcosbrightdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWhMar 226.9 kWhMar 226.9 kWhJun 44.5 kWhJun 44.5 kWhFeb 146.4 kWhFeb 146.4 kWhNowNow
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.
JanFebMarAprMayJunJulAugSepOctNovDec
Solar Energy (kWh) 5.96.56.96.35.04.75.45.14.64.75.35.5

For the purposes of this report, the geographical coordinates of San Marcos are 13.659 deg latitude, -89.183 deg longitude, and 2,421 ft elevation.

The topography within 2 miles of San Marcos contains very significant variations in elevation, with a maximum elevation change of 1,788 feet and an average elevation above sea level of 2,839 feet. Within 10 miles contains very significant variations in elevation (6,099 feet). Within 50 miles also contains extreme variations in elevation (8,182 feet).

The area within 2 miles of San Marcos is covered by trees (37%), cropland (30%), and grassland (28%), within 10 miles by cropland (33%) and trees (32%), and within 50 miles by water (31%) and cropland (28%).

This report illustrates the typical weather in San Marcos, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.

Temperature and Dew Point

There are 3 weather stations near enough to contribute to our estimation of the temperature and dew point in San Marcos.

For each station, the records are corrected for the elevation difference between that station and San Marcos according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.

The estimated value at San Marcos is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between San Marcos and a given station.

The stations contributing to this reconstruction are:

To get a sense of how much these sources agree with each other, you can view a comparison of San Marcos and the stations that contribute to our estimates of its temperature history and climate. Please note that each source's contribution is adjusted for elevation and the relative change present in the MERRA-2 data.

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , by Jean Meeus.

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for airports and weather stations are provided by AskGeo.com .

Maps are © OpenStreetMap contributors.

Disclaimer

The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.

We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.

Please review our full terms contained on our Terms of Service page.