We were on the June 19th Nile trip and had no problem getting Internet service. If you go out the back of the Cairo Marriott to July 26th Street and then cross the street to the side where Maison Thomas ( great Pizza at reaonable cost) walk to left ( when facing Maison Thomas) when you get to the Big Dollar Sign in Window turn right and about a block down is an Internet cafe on the right. The people are very nice inside. You can bring your laptop (netbook) as I did or use their computers. Cost is $2 per hour (10 Egyptian pounds)- very reasonable or $1 (5 LE) per half hour. Also in Aswan where the river boat docks there is a Cafe very close - walk out of ship and you will see signs. There is another close one not far in Luxor across street from boat and go up toward right - it costs $3 an hour. In Jordan we used the one at Geneva Hotel which was $4 an hour after you mentioned Jafar's name (the guide) and we were changed to the Movenpick Hotel in Petra and Internet was free there.
We were there in June so about the hottest time of year but the guides find you shade to stand in and the tours leave early to avoid heat. . I am usually bothered by the heat but managed without a problem. I think there is much less humidity than in NJ in the summer.