It does come with a rain cover. They are normally stashed in one of the side pockets on the bag. Try giving Titleist Customer Service a call for help.

800-742-7609

TH

Check with Golf Galaxy, they may have taken it out and sat it somewhere in the back of their shop. If the bag was discounted as a previous year's model, they may have known they lost the cover and you might just have to search the web for a used one. Nice thing is that the style hasn't changed so if GG can call Titleist, they may be able to get a 2018 replacement that matches.

Give all the pockets a thorough search. I recall having a similar experience with a new Titleist bag but it was well stashed in one of the pockets.

I see that as a good excuse for buying the Titleist rain towel bag hood!