I lived in Brussels for almost eight years. It is roughly 50 degrees north latitude. In North America, that puts it north of many well known Canadian cities.
Germany goes from about 48 degrees north latitude to over 54 degrees north latitude.
I never saw any mosquitoes or many bugs at all in Belgium, and my in-laws never reported any bugs when they were stationed in Germany.
When we had screens custom made to fit in our windows, the Belgian handyman who made them really didn’t understand what we wanted or why. He charged us a bunch of money and then I had to go down to the local Brico hardware store to buy the stuff I needed to fix them up to make them work the way we wanted. When he saw what I did, the next round of screens for other places in the house were much better made, and I didn’t have to fix them.
However, here in Texas, well boy howdy, you sure are going to want those bug screens on your windows. And there’s no practical way to make screens to fit into your silly casement Windows, so they better be properly made and affixed to the outside.
We didn’t have rolladen (rolling shades) in our house in Belgium. When we visited my in-laws in Germany, boy were we jealous. I’ve wanted something like proper German rolladen ever since. Oh, and their windows, too.