Cotton trench coat and the rain?

[Niftythrifter]

I have bought the classic style of trench coat in the Mango sale and before I pull the tags off I wondered how water resistant it could be. It doesn’t say it’s water repellent etc.

You can buy water repellent spray for clothes. Don't know if it's ok on cotton as I used it to top up my walking coat, but it may be worth trying.