Answers

Theoretically, there is no lower or upper temperature limit governing when asphalt fiberglass shingles may be applied as long as appropriate precautions are taken. 

? In cold weather, for easiest handling, temperatures should be above 40° F.
? In hot weather, for easiest handling, temperatures should be below 90° F. 

Those are the recommended temperatures, if you really need a need roof as long as you get 2 or more days above  30° F. you will be cover.