The best thing, I think, is to draw them out about their interests and hobbies. Ideally, you will find someone you share some interests and hobbies with and then you will have things to talk about.

Maybe you could start by mentioning some of yours, to see if they can relate....

Reading? Sports? Movies? Travel? whatever.

One thought, anyway.

And yes, the weather is a safe place to begin. Could lead to a mention of places you have lived and the weather there and giving them a chance to reciprocate.....