We are planning a trip to Paris in the Fall. Comparing the two months Sept. and Oct., which would have the most pleasant weather and least tourist crowds?

Neither will be particularly crowded and the weather will be about the same.

weather will be variable...someone could show you what has happened in the past but that is no guarantee that will happen during the time of your visit.

I guess it depends on your taste for weather. On average, October will be cooler, of course. NOt a lot else to say on that one, just typical fall weather in a moderate climate -- probably similar to NY city if you know that. I've been there both times, and towards beginning of Sept, you are more likely to be able to wear summer-ish cloths, of course. It can get downright nippy at night at end of month or October, but you can't predict for sure.

I don't think the tourist crowds will vary too much between those two months, Paris is a popular tourist city no matter what in nice weather, which is most of the year barring the dead of winter. There is much more business traffic (meaning visitors/people) in Sept/October, of course, like any capital city. If I were you, I'd choose based on prices or something you particularly want to do on a certain date, if any (ie, special exhibit or performance).

Be warned that Sept-Oct are THE peak hotel seasons in Paris, peak prices and you must book well in advance because it is so busy. This is due to business. That won't affect your crowds at the Eiffel Tower so much, I suppose.

I've gone to Paris several times in October, and love it then. I was there the last 2 weeks of Oct. in '09 and it was perfect in my opinion. As I live in South Florida I like it somewhat cool, but not COLD! I'm sure Sept. would be nice too, but a little warmer. I used the A/C in my hotel room at night - keeps the room quieter, and I'm used to A/C. I'm sure it wasn't necessary, but I like it and sleep better with it.

And about the crowds - I don't think sites are terribly crowded in October. But the Louvre was!
I had the Museum Pass, so lines were never an issue - and restaurants were fine, too. As Christina said, October (and Sept.) are prime time for business events/shows, etc. - so book hotel early.

We were there first week of October last year. As above, weather was variable, never hot, often cloudy, some showers, one truly sunny day. Had to buy a sweater one afternoon when it got cool and windy - my own fault, I should have taken a jacket.

Don't know about hotels (see above) because we stay in apartments, but the crowds were not overwhelming. Took a Seine boat ride at last minute and no trouble booking.

But be aware that some attractions have reduced schedules then, such as the Canal St. Martin boats.

Thanks for all the great info.

I was there late October last year and it was wonderful. Beautiful days and not very crowded.

If it would have worked out again, I would have gone back this year the same time, but due to other committments I can't go in October so am going in May (assuming the volcano gods have been satisfied by then )

We have gone to Paris in the beginning of Sept. since 2001. All years, except 2002 when it was a bit "nippy", the weather was perfect.

It's cool in the morning, by noon you are in short sleeves, and oddly enough, it's warm at night. We have enjoyed many night cruises on the Seine.

As far as crowds, 2009 was the most crowded we have seen Paris in all of our trips. We couldn't believe the lines at Notre Dame (we stay on Ile St. Louis) or the other sites. In other years, the lines were rather short.

This is just our experience.