I was thinking of going to Scandinavia, mostly Norway, in late May into June for about a month total. But then I was thinking instead to go late August into September. One of the travel books I was looking at said lots of places start to close up by September. I'm looking for experiences of people who may have traveled to Norway in September and what you thought of that. Thanks.

I have been in Denmark in September but not for a very very long time. Recently did Scandinavia this June. People I talked to in Norway told me that best time to visit is mid May to mid June. School summer holidays are mid June to mid August. Day light hours in June are something like 0400-2300. By September its something like 0600-2000 and by October its something like 0730 to 1830. Least amount of rain April through June and most rain July through October. Could get some snow in higher elevations in late September depending on where you go in Norway. The fjords get a lot of rain. It depends on what and where you want to go in Norway as to what things start to close down.

Mjs- thanks so much! This is helpful.

Depends on what you mean by most places.
September means a good chance of Aurora if you are even a little bit north. They tend to be more active around the equinox, and we are coming into a very active solar maximum period.