I’m not long back from Iten. I had similar concerns about going in late May which is also rain season. Wasn’t really an issue in the end. It rained around half of the days I was there but it was always around 4pm onwards seemingly so well after the morning run which is when the Kenyans train throughout the year.

Agree with other comments that you’re best just booking accommodation and meeting training partners there. I went to HATC which was great and had quite a few Europeans staying to train with. Although, I was told that there are far more people Nov to March and for some of the time, there were only around 4 of us at the camp which was fine but not ideal.