Is the Mountain Warehouse Rain On jacket actually waterproof?

Yes. It is sold as a waterproof jacket with a hooded polyester shell. Mountain Warehouse does not publish a waterproof rating for this model, so treat it as rain-proof for everyday and light hiking use rather than extreme weather.

How does the 3-in-1 design work?

The padded polyester inner jacket zips out of the waterproof outer shell. You can wear the shell alone in mild rain, the liner alone in dry cold, or both together for wet and cold days.

Is $103.99 a good price for this jacket?

The lowest recent daily price was $103.99 on November 3, against a high of $129.99 on November 1. That puts the current price at the bottom of its recent range, so it is a good time to buy if you need it.

What sizes does it come in?

It is a women's jacket, but the available size range and fit details are not specified in the product data. Check the size chart on the retailer's page before ordering, since 3-in-1 jackets often fit roomier to allow for the liner.

Is it warm enough for winter?

It is described as warm, with a 100% polyester fill in the removable liner. That suits cool to cold weather and layering, but it is not a heavy down parka for deep winter.