Hi, we have been in Paris since the 12th and it has been chilly every day except one day, and Wednesday was 80 degrees Fahr as the high for that day. The humidity is low, mornings and nights are cool. I have had on a sweater or jacket every day. We went to the top of the Eiffel last night and people were wrapped in warm coats (think quilted fall jackets, down vests, windbreakers layered over sweaters and etc.).
We are from the Phila, PA area and are used to 90+ degrees each summer day with 90+ humidity so the weather is cool for us. I wish I would have skipped the skirts and bermudas and brought another pair of long pants/khakis.
My point is, check the weather, weather.com before you go so you can relate the weather for your trip to what you are normally used to where you live.
We are having a great time!