My sister and I are arriving in Paris for 4 days on Sept. 19th, then off to London and a tour of Enland through the 29th. I know that northern England and Scotland should be pretty cool. I've looked up temp. averages for Paris and London (even though the weather this year has been anything but average) and it shows Paris averages 68 degrees F this time of year. I was planning to layer with short sleeves and sweaters over. My sister thinks that means she needs shorts. Is there any reason to think it will get warm enough to need shorts or warm-weather clothes. I hate to overpack and only like to bring essentials.

I know this is a miniscule thing, but any feedback is appreciated.

I wouldn't bother with shorts to be honest. You will be fine with light trousers. If there is a hot spell, you could always buy a pair. London is mild at the moment but I can feel it turning...

I would never ever take shorts to Paris and England at the end of Sept. Actually, I was in Paris in July when it was very hot and never wore them then.

That 68F is the average HIGH temp. There is no reason to take shorts on this trip. A jacket / raincoat would probably be more useful. Even in a hot weather (which 68 certainly isn't) a cotton skirt/dress or capris would be just as cool as shorts and MUCH more flexible re where you could wear them.

You will likely have decent weather - but definitely leave the shorts home.

As previous posters have said; don't take shorts. Even if it's warm enough to wear them, they really look out of place in Paris and London in late September. And even if it is warm in the afternoon, mornings and evenings will be cool. I live in Belgium, and cycle to school every morning with my kids; today it was only 10 celsius in the morning, even though it climbed to 24 in the afternoon.