Climate and Average Weather Year Round in San Rafael Arriba Costa Rica

In San Rafael Arriba, the wet season is humid and overcast, the dry season is partly cloudy, and it is warm year round. Over the course of the year, the temperature typically varies from 62°F to 80°F and is rarely below 59°F or above 83°F.

Based on the tourism score, the best time of year to visit San Rafael Arriba for warm-weather activities is from mid December to late March.

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

In San Rafael Arriba, 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 Rafael Arriba begins around November 24 and lasts for 4.5 months, ending around April 8.

The clearest month of the year in San Rafael Arriba is January, during which on average the sky is clear, mostly clear, or partly cloudy 62% of the time.

The cloudier part of the year begins around April 8 and lasts for 7.5 months, ending around November 24.

The cloudiest month of the year in San Rafael Arriba is June, during which on average the sky is overcast or mostly cloudy 95% of the time.

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

The wetter season lasts 6.9 months, from May 2 to November 29, with a greater than 29% chance of a given day being a wet day. The month with the most wet days in San Rafael Arriba is October, with an average of 15.4 days with at least 0.04 inches of precipitation.

The drier season lasts 5.1 months, from November 29 to May 2. The month with the fewest wet days in San Rafael Arriba is March, with an average of 2.5 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 Rafael Arriba is October, with an average of 15.4 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 52% on October 5.

Rainfall

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 Rafael Arriba experiences extreme seasonal variation in monthly rainfall.

Rain falls throughout the year in San Rafael Arriba. The month with the most rain in San Rafael Arriba is October, with an average rainfall of 6.5 inches.

The month with the least rain in San Rafael Arriba is March, with an average rainfall of 0.7 inches.

The length of the day in San Rafael Arriba does not vary substantially over the course of the year, staying within 42 minutes of 12 hours throughout. In 2024, the shortest day is December 21, with 11 hours, 33 minutes of daylight; the longest day is June 20, with 12 hours, 42 minutes of daylight.

The earliest sunrise is at 5:14 AM on May 28, and the latest sunrise is 45 minutes later at 5:58 AM on January 27. The earliest sunset is at 5:11 PM on November 15, and the latest sunset is 51 minutes later at 6:01 PM on July 11.

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

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.

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 Rafael Arriba experiences extreme seasonal variation in the perceived humidity.

The muggier period of the year lasts for 7.8 months, from April 11 to December 5, during which time the comfort level is muggy, oppressive, or miserable at least 16% of the time. The month with the most muggy days in San Rafael Arriba is June, with 14.5 days that are muggy or worse.

The month with the fewest muggy days in San Rafael Arriba is January, with 1.1 days that are muggy or worse.

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 Rafael Arriba experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 3.4 months, from December 19 to April 1, with average wind speeds of more than 2.5 miles per hour. The windiest month of the year in San Rafael Arriba is February, with an average hourly wind speed of 3.1 miles per hour.

The calmer time of year lasts for 8.5 months, from April 1 to December 19. The calmest month of the year in San Rafael Arriba is July, with an average hourly wind speed of 1.8 miles per hour.

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

The wind is most often from the west for 3.3 weeks, from May 21 to June 13 and for 2.2 months, from August 26 to November 1, with a peak percentage of 51% on September 30. The wind is most often from the east for 2.4 months, from June 13 to August 26 and for 6.6 months, from November 1 to May 21, with a peak percentage of 52% on July 22.

San Rafael Arriba 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 1°F of 83°F throughout.

To characterize how pleasant the weather is in San Rafael Arriba 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 Rafael Arriba for general outdoor tourist activities is from mid December to late March, with a peak score in the first week of January.

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 Rafael Arriba for hot-weather activities is from mid December to mid April, with a peak score in the second week of March.

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 Rafael Arriba 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.

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 significant seasonal variation over the course of the year.

The brighter period of the year lasts for 2.4 months, from February 1 to April 13, with an average daily incident shortwave energy per square meter above 6.2 kWh. The brightest month of the year in San Rafael Arriba is March, with an average of 6.7 kWh.

The darker period of the year lasts for 5.9 months, from May 19 to November 15, with an average daily incident shortwave energy per square meter below 4.3 kWh. The darkest month of the year in San Rafael Arriba is October, with an average of 3.8 kWh.

For the purposes of this report, the geographical coordinates of San Rafael Arriba are 9.876 deg latitude, -84.077 deg longitude, and 3,953 ft elevation.

The topography within 2 miles of San Rafael Arriba contains very significant variations in elevation, with a maximum elevation change of 1,430 feet and an average elevation above sea level of 4,095 feet. Within 10 miles contains very significant variations in elevation (6,027 feet). Within 50 miles also contains extreme variations in elevation (12,490 feet).

The area within 2 miles of San Rafael Arriba is covered by grassland (57%) and trees (32%), within 10 miles by trees (44%) and grassland (40%), and within 50 miles by trees (50%) and water (18%).