It depends upon where she's going. In Jerusalem, she can expect typical temperatures around 21C by day, dropping to around 12C overnight:
http://www.bbc.co.uk/weather/world/city_guides /city.shtml?tt=TT002440
However, Eilat would probably be much 'stickier', with moderate humidity and daytime temperatures reaching around 28C (falling to 16C overnight):
http://www.bbc.co.uk/weather/world/city_guides /city.shtml?tt=TT002420
Haifa has weather patterns roughly similar to those in Eilat::
http://www.bbc.co.uk/weather/world/city_guides /city.shtml?tt=TT002430
Chris