Six days in Bern doing day trips from there

You do not need AC that badly in the first week of June, and especially not in the highlands.
While Bern is lovely and indeed very central, perhaps try relaxing this criteria in your accommodation search? You should be able to find rooms for about 200 Swiss francs (except perhaps in Zermatt), and you might be looking a bit early - many hotels won't have opened June 2024 bookings yet.

Yes, workable. Bern's a nice city. It wouldn't be my first choice for a "base" city. But, it will be nice. Hard to go wrong in Switzerland. I used VRBO in Lauterbrunnen. Did you happen to check VRBO or AirBnB? Also, Gimmelwald often has less expensive accommodations, but you'd need to go up to Murren or down to Lauterbrunnen for more restaurants/things to do. Gimmelwald is in a beautiful setting.

Balso makes a good point about AC. I don't think its necessary, either. Why don't you put some of those cities in a weather app and follow the weather for a few weeks. I don't think it gets terribly hot.

Bern is a very good base to travel from for day trips. If you cannot do much hiking there seems to be no need to be based in the Alps. Look at the Hotel Savoy. Nice hotel, close to the train and has AC. If you wake up one morning and check the weather and it is clear in Zermatt, head that way to see the Matterhorn. All the places you name and more are very easy to reach from Bern. Enjoy your trip!

Train travel in Switzerland is expensive. If you add up the fares for roundtrip travel to all those different places from Bern, it will add a considerable amount to the cost of basing in one spot.

For example, Bern to Zermatt is around 75-85 CHF each way. So roundtrip for 2 people is 4times that. I just priced a journey for tomorrow and it came to 346 CHF, just for that one day. And you will be spending almost 5 hours of that day on trains or waiting in train stations.

That is the most expensive trip. The others come in the range of 100-140 CHF for the two of you. But you will still be spending a considerable amount of time ion trains and in train stations.

You can reduce your costs by buying Half Fare Cards for each of you, but that will cost another 240 CHF.

aroma, do what you feel comfortable with. To me, part of the specialness of being in Switzerland is being in the mountains, and especially waking up to mountain views or going to bed with the quiet of the mountain valleys around you. So Bern, not being in the mountains, would seem to me like trying to visit New York City by staying in New Jersey, or visiting California by staying in Fresno (dont know here you live).

Presumably, you'll be out in the weather every day so you only need the AC at night, right? When you look at the daily temps, look at the daily lows, not the highs. That tells you more closely what you'll be sleeping in. And note even if the train ride itself is only about an hour, it takes time to get to and from the rail station, wait for trains and then get to the sight you're planning to see. So that instead of two hours a day, that becomes more like 3-4. Thats too much for me.

HOTELS: You are not finding availability because many hotels in Switzerland have not opened up booking yet for next summer. I know this because I am also booking my trip for next June. Still waiting to book hotels in Wengen and Zermatt. I would check back mid to end of August. That is still early enough that you should benefit from booking early.

JUNE WEATHER: I was in Switzerland June 2021 (June 5 – June 19) and it was a warm June. The only place that I wished I had a/c was in Lucerne. I was warmer outside than in any of my hotels (even in Lucerne) because that Swiss sun is hot!!! That’s what I would worry more about. I recommend a hat and some good sunscreen.

Having been to Bern, that is not a place I would choose for a home-base. I would much rather be based in Lucerne or Murren/Wengen/Lauterbrunnen for a week.

So, i would definitely wait a month or so to see what your hotel options are and make your decision based on what's available then.

You might consider Thun rather than Bern as your base. I visited each of them as day trips only, but I would love to return and stay for a week in Thun! I personally would deprioritize Zurich on this trip and devote your time to the other areas. From Lauterbrunnen, you can easily visit Wengen by train and it's a wonderful, car-free village. I've read mixed reviews of Gruyere on this forum but have not been there myself.

I totally agree with Threadwear - no need to stay up into the mountains when that is not the kind of holiday you are looking for. Bern would be an excellent base, it is a lovely city and has many, many train connections daily. You can go anywhere from there - and relatively quickly because you don’t have the winding lake or slow mountain routes to deal with just to get in and out of there, like you do in many other locations...especially mountain villages.

You mention Thun - this is also a great location. There is a lot to do here and also some good train connections. Lots of local mountains to look at and head up for the day if you desire, and it is right on the lake.

As Carrie says, just waiting a bit longer will probably open up some more hotel options. You could choose where you want to be and wait to see what opens up.

Lola is correct that the trains are expensive, but you can research ways to lower your costs such as Super Saver Day passes or Saver tickets for specific routes, as well as other passes that are available to tourists. I would not restrict myself in terms of traveling around - just spend some time to find the cheapest way to do it. Once you come all the way here is would be a great shame not to explore the country a bit!

If you wake up and its clear in Bern, the weather could be quite different by the time you get to Zermatt, similarly Jungfraujoch, Rigi, Schilthorn. There is so much in Lucerne and Lauterbrunnen, even without hiking, I think you'd end up going back multiple times. I still think Bern would be an ok spot to base, but if you can get lodging to meet your requirements in Lucerne or Lauterbrunnen/BO, I think that would be so much better. You will be spending less time on a train.