My sister and I just cancelled our October trip to Lauterbrunnen and Paris. We are planning to go in June 2021. What are the bugs like at that time? Are there a lot of mosquitoes or biting flies?
I don't recall bugs being a pest during June in that area. Flies might be an issue if you're hanging around some of the cows and barns for obvious reasons, but not if you're on the hiking trails, milling about town, or walking up and down the valley. I even brought bug spray once and never used it.
I frequently visit various parts of Switzerland in June - not this year though.
We carry a plug-in bug coil and a anti-bug liquid we rub on. We use those in parts of Italy, Germany and France, sometimes a bit later in the year.
We have never applied the liquid or plugged in the device in Switzerland, in any month.
You will have flies in and near facilities with livestock.
I have stayed in Bern, Zurich, Murren and Chur in Switzerland in June and never noticed any problems with bugs.