Here, when you don’t know what to talk about, you just talk about the weather. You simply can’t get wrong if you stick to this rule. If there is an awkward silence, all you have to do is to say something like “terrible weather, isn’t it?” and you are sure that the conversation will pick up. Guaranteed.
But be prepared: talking about the weather can happen anywhere, even in the most unexpected places. At work, I went to the loo the other day and the lady who was washing her hands next to me started a passionate conversation about how cold the weather had been over half term. I ended up having to pretend that I had an urgent meeting otherwise we would probably have spent the whole afternoon chatting away and we would still be there. I kid you not. That’s how intense the whole exchange was.