Not always. First, at least in my experience, our short rainy season means it can be quite chilly. Second, nights are cold, especially because there's no heater. Third, it may be hot during the day, but cold during the early morning, when you're leaving.
Advice? Bring a sweatshirt for nights, when you're in the house. Buy some cute shawls for during the day. That way, you can wear shorter sleeves but still keep yourself warm in the morning. This also works for modesty, as it is unacceptable to show your knees and shoulders most places (even in places where it may be acceptable, you may attract double attention if you're white). Also, you'll have something cute from Kenya.