Weather will likely play an important role when you plan your trip to Siaya, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually February and March, with an average temperature of 24°C, while the coldest months are June and July, with an average of 22°C. The rainiest months in Siaya are April, May, November and October, with each month seeing an average of 306 mm of rainfall.