Hi Samra2,
Going back to the original topic, the weather here in summer is very similar to Beirut. It's warm and humid, but it shouldn't bother you.
Don't worry about being lonely in Baires, you're gonna meet very many amazing people, expats as well as locals. I'd recommend you to share a house if you don't have an accomodation yet. If you need I can ask around too, a couple of friends with a houses and parrilla are regularly looking for flatmates.
If you need tips or wanna talk about Baires, my brother currently lives in Beirut. I'm sure he'd be glad to help you out.
I won't be here for the holidays, but if you need anything or wanna meet for coffee or lebanese food some other timelet me know!
Cheers!