I have also been going a bit stir crazy being home all day long with my 5 week old so we’ve been going out on daily walks outside though I try to be mindful of the time and not stay out too long as here in Poland it’s getting quite nippy already and I don’t want him to get sick (though I make sure to bundle up!!)
We did this when our daughter was maybe a week old did it with both kids and no issues my pediatrician said nothing about it being bad because if you bundle them in layers than you are fine we do a fleece onsie and then we have these LL bean winter bear suits that keep them really warm and our kids love a snowy walk in Colorado especially in the mountains.
I’ve been taking walks with my 1-month old in about 30-35 degrees weather. I just make sure to dress him accordingly and keep it to 30 minutes for my peace of mind. He seems fine with it! I also go for drives when it seems too cold to me and I still need out of the house.
I have heard a lot of mixed reviews and would check with the pediatrician. Ours wants us limiting time outdoors when it’s under freezing due to the impact on his lungs, but I have also heard differently. We are also stir crazy with a 5 week old and have been going on a lot of drives to try to cope.