My wife and i arrive on the 4th, ive been
icmeler twice in may, belek and alanya and have allways had very good weather, it can get a tad chilly on an evening (13-17) but normally its fine.
Day times can be fairly warm 23-27 but there is allways a chance of a cooler, cloudy, raining day or 2 early may.
Its still better than the uk, hope u and your family have a nice time.