December Weather in San Rafael Costa RicaDaily high temperatures are around 76°F, rarely falling below 72°F or exceeding 80°F. Daily low temperatures are around 63°F, rarely falling below 59°F or exceeding 65°F. The highest daily average low temperature is 63°F on December 22. For reference, on April 8, the hottest day of the year, temperatures in San Rafael typically range from 63°F to 80°F, while on September 20, the coldest day of the year, they range from 62°F to 76°F. The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on December. 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. Kibangay, Philippines (10,095 miles away) is the far-away foreign place with temperatures most similar to San Rafael (view comparison). CloudsThe month of December in San Rafael experiences very rapidly decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 60% to 36%. The clearest day of the month is December 31, with clear, mostly clear, or partly cloudy conditions 64% of the time. For reference, on June 4, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 95%, while on January 2, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 64%. PrecipitationA wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In San Rafael, the chance of a wet day over the course of December is very rapidly decreasing, starting the month at 28% and ending it at 13%. For reference, the year's highest daily chance of a wet day is 51% on October 6, and its lowest chance is 6% on March 15. RainfallTo 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 December in San Rafael is rapidly decreasing, starting the month at 3.0 inches, when it rarely exceeds 6.5 inches or falls below 0.5 inches, and ending the month at 1.4 inches, when it rarely exceeds 3.3 inches or falls below 0.1 inches. SunOver the course of December in San Rafael, the length of the day is essentially constant. The shortest day of the month is December 21, with 11 hours, 33 minutes of daylight and the longest day is December 1, with 11 hours, 35 minutes of daylight. The earliest sunrise of the month in San Rafael is 5:38 AM on December 1 and the latest sunrise is 15 minutes later at 5:53 AM on December 31. The earliest sunset is 5:13 PM on December 1 and the latest sunset is 13 minutes later at 5:26 PM on December 31. Daylight saving time is not observed in San Rafael during 2024. For reference, on June 20, the longest day of the year, the Sun rises at 5:16 AM and sets 12 hours, 43 minutes later, at 5:59 PM, while on December 21, the shortest day of the year, it rises at 5:48 AM and sets 11 hours, 33 minutes later, at 5:21 PM. 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. MoonThe figure below presents a compact representation of key lunar data for December 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. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.
HumidityWe 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 Rafael is rapidly decreasing during December, falling from 16% to 5% over the course of the month. For reference, on June 1, the muggiest day of the year, there are muggy conditions 49% of the time, while on January 24, the least muggy day of the year, there are muggy conditions 2% of the time. WindThis 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 Rafael is gradually increasing during December, increasing from 3.0 miles per hour to 3.8 miles per hour over the course of the month. For reference, on February 5, the windiest day of the year, the daily average wind speed is 4.0 miles per hour, while on September 17, the calmest day of the year, the daily average wind speed is 1.8 miles per hour. The hourly average wind direction in San Rafael throughout December is predominantly from the east, with a peak proportion of 69% on December 29. Water TemperatureSan Rafael 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 Rafael is essentially constant during December, remaining around 82°F throughout. The lowest average surface water temperature during December is 82°F on December 5. Growing SeasonDefinitions 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 Rafael 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. 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. The average accumulated growing degree days in San Rafael are rapidly increasing during December, increasing by 544°F, from 6,178°F to 6,721°F, over the course of the month. Solar EnergyThis 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 Rafael is gradually increasing during December, rising by 0.7 kWh, from 4.7 kWh to 5.5 kWh, over the course of the month. TopographyFor the purposes of this report, the geographical coordinates of San Rafael are 10.013 deg latitude, -84.100 deg longitude, and 4,144 ft elevation. The topography within 2 miles of San Rafael contains very significant variations in elevation, with a maximum elevation change of 1,355 feet and an average elevation above sea level of 4,168 feet. Within 10 miles contains very significant variations in elevation (7,142 feet). Within 50 miles also contains extreme variations in elevation (11,447 feet). The area within 2 miles of San Rafael is covered by grassland (49%), trees (33%), and cropland (13%), within 10 miles by trees (44%) and grassland (42%), and within 50 miles by trees (57%) and grassland (17%). Data SourcesThis report illustrates the typical weather in San Rafael, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016. Temperature and Dew PointThere 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 Rafael. At a distance of 12 kilometers from San Rafael, 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 Rafael 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 DataAll 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. DisclaimerThe 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. |