Jan 28, 2017 - 4:23 PM
Hi swissfans, welcome to MySwissAlps!
Here are some resources that may be relevant:
- MeteoSwiss climate diagrams. You can look for temperature and precipitation averages for several Swiss measuring stations across the country, either through a map or using the table. You'd best look for stations in the (wider) Aletsch area and locations at the approximate altitude you're interested in. Grimsel Hospiz and Gütsch ob Andermatt may serve as examples.
- MeteoSwiss monthly and annual maps. This provides good insight in sunshine, temperature and precipitation averages throughout the country. It's a bit harder to find the precise heights though.
Please note that these are just averages and that they have limited predicting value for next May and June. Circumstances can strongly vary per year, season, month and day, and forecasts only start to become reliable a couple of days in advance. Please see myswissalps.com/weathe r for more information and links.
Bettmerhorn-Fiescheralp could be tricky in May and June. Trails at such altitude can still be covered in snow and are likely to still be inaccessible, unless there's been warm and dry Spring weather. Also, mind that the cable car to Fiescheralp/Eggishorn won't be fully operational before June 10. July to September are the best months for high altitude hikes. You'll find plenty of pleasant trails at lower altitude for May and June though.
I hope this helps!