The rainfall pattern in Busia municipality is typically bimodal, with the first rainy season extending from March to May and a longer rainy season from August to November. The annual rainfall varies from a minimum of 1,080 mm to a maximum of 1,940 mm, with a mean of 1,514 mm (Busia District Report, 2009). It can be seen that potential evapotranspiration varies between a maximum of 150 and a minimum of 115 mm/month. Temperatures are relatively high varying between 160c and 310c. Mean Annual Maximum temperature is 28.70C and the Mean Annual Minimum is 16.20C. The mean monthly maximum ranges from 270C to 310C, while the mean monthly minimum sometimes falls to 160C especially at dawn (early morning).
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Busia, the chance of a wet day over the course of June is very rapidly decreasing, starting the month at 57% and ending it at 42%. For reference, the year’s highest daily chance of a wet day is 78% on April 29, and its lowest chance is 21% on January 23.
The month of June, Busia experiences gradually decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 68% to 62%. The clearest month of the year is June, with clear, mostly clear, or partly cloudy conditions 38% of the time. For reference, on April 16, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 83%, while on August 30, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 50%.
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 and in Busia it rapidly decreases during June, falling from 90% to 73% over the course of the month. For reference, on May 11, the muggiest day of the year, there are muggy conditions 95% of the time, while on January 4, the least muggy day of the year, there are muggy conditions 51% of the time.