1. WeatherSpark.com
  2. Costa Rica
  3. San José
  4. San Marcos
  5. October

Average Weather in October in San Marcos Costa Rica

In San Marcos, the month of October is characterized by essentially constant daily high temperatures, with daily highs around 71°F throughout the month, rarely exceeding 75°F or dropping below 67°F. The lowest daily average high temperature is 70°F on October 27.

Daily low temperatures are around 59°F, rarely falling below 56°F or exceeding 61°F. The lowest daily average low temperature is 58°F on October 2.

For reference, on March 28, the hottest day of the year, temperatures in San Marcos typically range from 60°F to 75°F, while on October 2, the coldest day of the year, they range from 58°F to 71°F.

Average High and Low Temperature in October

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.

The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on October. The horizontal axis is the day, 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 October

Average Hourly Temperature in October in San Marcos12 AM4 AM8 AM12 PM4 PM8 PM12 AM181522291122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930303131SepNovcoolcomfortable
The average hourly temperature, color coded into bands: frigid < 15°F < freezing < 32°F < chilly < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The shaded overlays indicate night and civil twilight.

Clouds

The month of October in San Marcos experiences gradually decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 95% to 88%. The highest chance of overcast or mostly cloudy conditions is 95% on October 2.

The clearest day of the month is October 31, with clear, mostly clear, or partly cloudy conditions 12% of the time.

For reference, on June 5, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 96%, while on January 2, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 63%.

Cloud Cover in October

The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds: clear < 20% < mostly clear < 40% < partly cloudy < 60% < mostly cloudy < 80% < overcast.

Precipitation

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In San Marcos, the chance of a wet day over the course of October is decreasing, starting the month at 52% and ending it at 46%.

For reference, the year's highest daily chance of a wet day is 53% on October 7, and its lowest chance is 8% on March 16.

Probability of Precipitation in October

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).

Rainfall

To show variation within the month and not just the monthly total, we show the rainfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day rainfall during October in San Marcos is decreasing, starting the month at 6.7 inches, when it rarely exceeds 12.1 inches or falls below 2.8 inches, and ending the month at 6.0 inches, when it rarely exceeds 11.3 inches or falls below 2.2 inches.

The highest average 31-day accumulation is 6.8 inches on October 12.

Average Monthly Rainfall in October

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 liquid-equivalent snowfall.

Sun

Over the course of October in San Marcos, the length of the day is essentially constant. The shortest day of the month is October 31, with 11 hours, 47 minutes of daylight and the longest day is October 1, with 12 hours, 2 minutes of daylight.

Hours of Daylight and Twilight in October

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.

The earliest sunrise of the month in San Marcos is 5:24 AM on October 10 and the latest sunrise is 1 minute, 50 seconds later at 5:26 AM on October 31.

The latest sunset is 5:26 PM on October 1 and the earliest sunset is 13 minutes earlier at 5:13 PM on October 31.

Daylight saving time is not observed in San Marcos during 2017.

For reference, on June 21, the longest day of the year, the Sun rises at 5:17 AM and sets 12 hours, 41 minutes later, at 5:58 PM, while on December 21, the shortest day of the year, it rises at 5:47 AM and sets 11 hours, 34 minutes later, at 5:21 PM.

Sunrise & Sunset with Twilight in October

The solar day over the course of October. 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.

Humidity

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.

The chance that a given day will be muggy in San Marcos is decreasing during October, falling from 38% to 29% over the course of the month.

For reference, on June 1, the muggiest day of the year, there are muggy conditions 44% of the time, while on January 24, the least muggy day of the year, there are muggy conditions 2% of the time.

Humidity Comfort Levels in October

Humidity Comfort Levels in October in San Marcos0%10%20%30%40%50%60%70%80%90%100%181522291122334455667788991010111112121313141415151616171718181919202021212222232324242525262627272828292930303131SepNovOct 138%Oct 138%Oct 3129%Oct 3129%Oct 1136%Oct 1136%Oct 2134%Oct 2134%muggymuggyhumidhumidcomfortablecomfortabledrydryoppressiveoppressive
The percentage of time spent at various humidity comfort levels, categorized by dew point: dry < 55°F < comfortable < 60°F < humid < 65°F < muggy < 70°F < oppressive < 75°F < miserable.

Wind

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 is essentially constant during October, remaining within 0.1 miles per hour of 1.6 miles per hour throughout.

For reference, on October 8, the windiest day of the year, the daily average wind speed is 1.7 miles per hour, while on December 15, the calmest day of the year, the daily average wind speed is 0.9 miles per hour.

The highest daily average wind speed during October is 1.7 miles per hour on October 8.

Average Wind Speed in October

The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.
The hourly average wind direction in San Marcos throughout October is predominantly from the west, with a peak proportion of 71% on October 1.

Wind Direction in October

The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions (north, east, south, and west), excluding hours in which the mean wind speed is less than 1 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Water Temperature

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 surface water temperature in San Marcos is essentially constant during October, remaining around 82°F throughout.

Average Water Temperature in October

The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

Solar Energy

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 in San Marcos is essentially constant during October, remaining within 0.1 kWh of 3.7 kWh throughout.

The lowest average daily incident shortwave solar energy during October is 3.6 kWh on October 11.

Average Daily Incident Shortwave Solar Energy in October

The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

For the purposes of this report, the geographical coordinates of San Marcos are 9.660 deg latitude, -84.020 deg longitude, and 5,266 ft elevation.

The topography within 2 miles of San Marcos contains large variations in elevation, with a maximum elevation change of 2,411 feet and an average elevation above sea level of 5,035 feet. Within 10 miles contains large variations in elevation (9,304 feet). Within 50 miles also contains extreme variations in elevation (12,490 feet).

The area within 2 miles of San Marcos is covered by trees (42%), grassland (30%), shrubs (16%), and cropland (13%), within 10 miles by trees (64%) and grassland (19%), and within 50 miles by trees (43%) and water (30%).

Data Sources

This report illustrates the typical weather in San Marcos year round, 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 is only a single weather station, Juan Santamaría International Airport, in our network suitable to be used as a proxy for the historical temperature and dew point records of San Marcos.

At a distance of 43 kilometers from San Marcos, closer than our threshold of 150 kilometers, this station is deemed sufficiently nearby to be relied upon as our primary source for temperature and dew point records.

The station records are corrected for the elevation difference between the 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.

Please note that the station records themselves may additionally have been back-filled using other nearby stations or the MERRA-2 reanalysis.

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , 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 aiports and weather stations are provided by AskGeo.com .

Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.