Average Weather in Athi River Kenya

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2. Kenya
3. Machakos
4. Athi River

The climate in Athi River is warm, windy, and mostly cloudy. Over the course of the year, the temperature typically varies from 55°F to 83°F and is rarely below 50°F or above 87°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.

In Athi River, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year in Athi River begins around June 24 and lasts for 3.5 months, ending around October 10. On September 1, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 59% of the time, and overcast or mostly cloudy 41% of the time.

The cloudier part of the year begins around October 10 and lasts for 8.5 months, ending around June 24. On April 2, the cloudiest day of the year, the sky is overcast or mostly cloudy 74% of the time, and clear, mostly clear, or partly cloudy 26% 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 Athi River varies significantly throughout the year.

The wetter season lasts 6.8 months, from October 22 to May 17, with a greater than 23% chance of a given day being a wet day. The chance of a wet day peaks at 44% on April 21.

The drier season lasts 5.2 months, from May 17 to October 22. The smallest chance of a wet day is 2% on July 20.

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 44% on April 21.

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. Athi River experiences significant seasonal variation in monthly rainfall.

The rainy period of the year lasts for 8.0 months, from October 5 to June 4, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around April 20, with an average total accumulation of 2.9 inches.

The rainless period of the year lasts for 4.0 months, from June 4 to October 5. The least rain falls around July 10, with an average total accumulation of 0.1 inches.

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

The earliest sunrise is at 6:10 AM on November 6, and the latest sunrise is 31 minutes later at 6:41 AM on February 14. The earliest sunset is at 6:20 PM on October 30, and the latest sunset is 31 minutes later at 6:51 PM on February 8.

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

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 Athi River, 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, remaining a virtually constant 0% throughout.

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 Athi River experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 7.8 months, from August 30 to April 24, with average wind speeds of more than 4.7 miles per hour. The windiest day of the year is December 9, with an average hourly wind speed of 5.8 miles per hour.

The calmer time of year lasts for 4.2 months, from April 24 to August 30. The calmest day of the year is June 17, with an average hourly wind speed of 3.7 miles per hour.

The predominant average hourly wind direction in Athi River is from the east throughout the year.

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 2.0 months, from January 24 to March 24, with an average daily incident shortwave energy per square meter above 7.2 kWh. The brightest day of the year is March 7, with an average of 7.5 kWh.

The darker period of the year lasts for 2.3 months, from May 30 to August 9, with an average daily incident shortwave energy per square meter below 6.2 kWh. The darkest day of the year is June 20, with an average of 5.9 kWh.

For the purposes of this report, the geographical coordinates of Athi River are -1.456 deg latitude, 36.978 deg longitude, and 5,013 ft elevation.

The topography within 2 miles of Athi River contains only modest variations in elevation, with a maximum elevation change of 292 feet and an average elevation above sea level of 4,998 feet. Within 10 miles contains only modest variations in elevation (1,266 feet). Within 50 miles contains very significant variations in elevation (6,785 feet).

The area within 2 miles of Athi River is covered by grassland (55%), cropland (19%), artificial surfaces (14%), and trees (11%), within 10 miles by grassland (58%) and shrubs (30%), and within 50 miles by grassland (29%) and cropland (26%).

This report illustrates the typical weather in Athi River, 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 2 weather stations near enough to contribute to our estimation of the temperature and dew point in Athi River.

For each station, the records are corrected for the elevation difference between that station and Athi River 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 Athi River is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Athi River and a given station.

The stations contributing to this reconstruction are: Jomo Kenyatta International Airport (95%, 16 kilometers, north) and Makindu Airport (4.6%, 132 kilometers, southeast).

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.