There are a few good times to come and visit the lake and that mostly depends on what kind of weather you are looking for. The cooler weather comes in July and August.
The rest of the time there is a lot of rain in the area and some of the rains are long and short. The longer rains are experienced mostly during April, May and again in August. While during October and December the long rains are common.
The months with the hotter temperature includes January, February and March.
The best times to come and visit if you don't want to get caught in the rain are January until March, June, July, September and November. However, the final decision also depends on what temperature you are willing to deal with.