Average Weather in Oyem Gabon

The climate in Oyem is warm, oppressive, and overcast. Over the course of the year, the temperature typically varies from 66°F to 83°F and is rarely below 65°F or above 86°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

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

In Oyem, the average percentage of the sky covered by clouds experiences mild seasonal variation over the course of the year.

The clearer part of the year in Oyem begins around May 28 and lasts for 3.0 months, ending around August 27. On July 9, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 29% of the time, and overcast or mostly cloudy 71% of the time.

The cloudier part of the year begins around August 27 and lasts for 9.0 months, ending around May 28. On March 31, the cloudiest day of the year, the sky is overcast or mostly cloudy 85% of the time, and clear, mostly clear, or partly cloudy 15% of the time.

Cloud Cover

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. The chance of wet days in Oyem varies very significantly throughout the year.

The wetter season lasts 8.5 months, from September 11 to May 26, with a greater than 49% chance of a given day being a wet day. The chance of a wet day peaks at 87% on October 30.

The drier season lasts 3.5 months, from May 26 to September 11. The smallest chance of a wet day is 9% on July 24.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 87% on October 30.

Daily Chance of Precipitation

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 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. Oyem experiences extreme seasonal variation in monthly rainfall.

Rain falls throughout the year in Oyem. The most rain falls during the 31 days centered around October 24, with an average total accumulation of 11.0 inches.

The least rain falls around July 24, with an average total accumulation of 0.7 inches.

Average Monthly Rainfall

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

The length of the day in Oyem does not vary substantially over the course of the year, staying within 12 minutes of 12 hours throughout. In 2017, the shortest day is December 21, with 12 hours, 2 minutes of daylight; the longest day is June 21, with 12 hours, 13 minutes of daylight.

Hours of Daylight and Twilight

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 is at 5:55 AM on October 31, and the latest sunrise is 31 minutes later at 6:26 AM on February 8. The earliest sunset is at 5:58 PM on November 5, and the latest sunset is 31 minutes later at 6:29 PM on February 13.

Daylight saving time (DST) is not observed in Oyem during 2017.

Sunrise & Sunset with Twilight

The solar day over the course of the year 2017. 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 perceived humidity level in Oyem, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, staying within 4% of 96% throughout.

Humidity Comfort Levels

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 Oyem does not vary significantly over the course of the year, remaining within 0.1 miles per hour of 0.8 miles per hour throughout.

Average Wind Speed

The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

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

The wind is most often from the south for 3.1 weeks, from April 19 to May 11, with a peak percentage of 45% on May 3. The wind is most often from the west for 11 months, from May 11 to April 19, with a peak percentage of 65% on January 1.

Wind Direction

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).

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 per square meter does not vary significantly over the course of the year, remaining within 0.3 kilowatt-hours of 4.6 kilowatt-hours throughout.

Average Daily Incident Shortwave Solar Energy

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 Oyem are 1.599 deg latitude, 11.579 deg longitude, and 2,159 ft elevation.

The topography within 2 miles of Oyem contains only modest variations in elevation, with a maximum elevation change of 348 feet and an average elevation above sea level of 2,153 feet. Within 10 miles contains only modest variations in elevation (797 feet). Within 50 miles contains significant variations in elevation (1,929 feet).

The area within 2 miles of Oyem is covered by trees (31%), cropland (27%), grassland (24%), and shrubs (18%), within 10 miles by trees (78%) and grassland (12%), and within 50 miles by trees (73%) and grassland (12%).

Data Sources

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

Oyem is further than 200 kilometers from the nearest reliable weather station, so the weather-related data on this page were taken entirely from NASA's MERRA-2 satellite-era reanalysis . 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.

The temperature and dew point estimates are corrected for the difference between the reference elevation of the MERRA-2 grid cell and the elevation of Oyem, according to the International Standard Atmosphere .

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.

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.