I will be in Europe in October also and I have the same question. I have seen it posted here before and have done so myself, but no response. I think most of the members travel during summer. Tell you what I’ll do. I will check with a couple of folks I know who live on the East coast where it gets pretty cold. If you’ve found any info, please add it here.
Thank you.

I backpacked in England and Scotland in November before. It’s great because there are very few tourists there. Not so great because it literally rained (on and off) all day every day. But I went expecting it. Make sure to take a wind proof/waterproof jacket and waterproof shoes/boots (i had these really good waterproof hiking boots. i highly recommend it)
coming from australia you’ll find it cold. even for me coming from northern alberta, i found it to be a very bone chilling, damp cold (different from what im used to). bring some tshirts and longer sleeve shirts, that way you can layer and remove the layers as it warms up.
have a great trip!

I don’t think you’ll find too much snow or below-zero temperatures in October in the countries you listed. Probably more rain, chilly weather, wind and overall greyness.

Take a good waterproof jacket that also offers some insulation/warmth, a good pair of waterproof shoes, and I agree with the people who said to layer. Also, remember that there’s a difference between walking from your office to your car in chilly weather, and walking around outdoors all day.

Oh, and cover your ears. If your ears are covered, the rest of you will feel better.

cheers thanks for the help.