Winter back carrying: what to wear

[SecondTimer2019]

I have a chunky 6 month old who I need to carry on the nursery run (2.5yr old in buggy).

I have been front carrying up to now but finding it less and less convenient and want to try back carrying, but... What do I wear?

Do I put it on over my coat (presumably yes!). I have quite a bulky cost and not sure how this is going to work.

How can I keep baby covered in the rain? Is there a cover that's easy to put on for back carrying?

Should have said I'm using an Ergo 360.

My local Sling library just shared this recently

Yes, a babywearing coat like the Mam one. There are many others, perhaps look on ebay. Or a very big umbrella.