Ours is 14 months now, started crawling at 7 months, walking reliably at about 12 and a half. If yours is anything like mine, she won't be content to just sit in the tent and watch the world go by; mine threw a screaming fit when I tried to bring her in the house when the rain started, and yesterday was supremely happy to sit in the garden playing with the dirt. I would suggest you're going to need *something* in the next 6 months; at bare minimum they're crawling around and her town jacket won't cut it in the yard, nevermind the outdoors. Right now she wears a fleece lined rain coat-type jacket, and I've got a
one piece rain suit for when we're out camping.
You say you'll just use her town jacket "for a few years"; I don't think that's terribly realistic. I can't imagine a 2 or 3 year old not going out in the rain/snow and getting down and dirty, and I'm certainly not going to carry mine for the entire time when she's 3. Heck, it doesn't have to be raining for a little one to be digging in the dirt, and I like to have at least a jacket she can get messy and still have a going-out jacket.