Can't seem to find a good accurate forecast for Wengen. We will be there 6/1 - 6/5. Does it get down to the 30's at night there? We're trying to make sure we pack appropriately. Thanks!

Weather is quite changeable in the mountains, and June is unpredictable. I would bring layers that you can add or take off as the weather dictates. It could be in the 80s and it could be in the 40s, and can quite easily be both on the same day. You may have cloudy and cool/rainy or foggy weather, which can quickly change to sunny weather (Switzerland is a place where if you don’t like the weather, wait 10 minutes). It is quite unlikely to be in the 30s and snowing in Wengen even at night (but certainly there will be a lot of snow up on top of the Jungfrau and it will be very cold and could easily be snowing). If you do the Maennlichen to Kleine Scheidegg walk, you will encounter some remaining patches of snow on the ground and the trail will be wet/muddy. Bring cotton sweaters and long sleeve T-shirts or turtlenecks (or both), a warmish waterproof jacket (one with a removable lining is best IMO), gloves and hat, an umbrella, warm socks, and good waterproof shoes. A wool scarf if easy to pack and would be useful (same with the hat and gloves). I don’t think wool sweaters are necessary if you have several layers of cotton.

Wait until the day before you leave. Then check weather.com or accuweather.com for updates. We were in Wengen June 10 and it was 75. Do not overpack. We hiked all over the BO and never took our jackets or layers out of the suitcase. If you're going to the "Top of Europe" that's different.