May to October is the warm period and November through April is the cooler period, but also when all rain occurs. It is still quite warm during this cooler period, but also less crowded and with less air pollution in Cairo so that's a plus also. Pricing is less expensive since the crowds are down.

Don't think about July / August. It's VERY crowded, prices are high and the pollution is awful in Cairo.

Alexandria on the coast is much cooler than the domestic areas, so a visit there on the edge of the hot season might be more comfortable temperature-wise than the "cool" season in the domestic areas.

Now is a nice time to visit. Actually, if you want to time it with holidays, then Christmas would be a good time, as well.

My colleague is an Egyptian; I will as her when I go into the office this afternoon.

Its a little cold nowadays in Cairo (by Cairine standards)...come in a month's time and it'll be perfect :)