Yep, Swiss weather. Unpredictable everywhere, really.

I do like the mountains in the Mattertal and have spent my time on the side of the Matterhorn (OK, the Hirli) in a small, aluminum 'tent' with winds and snow howling outside and a 5-year old inside with me and my wife. :) That being said, I have seen mountains just as pretty in many other places in Switzerland.

Grindelwald is a great base for hiking, especially lower altitude hiking. Wengen is a great place with lifts to hiking in a beautiful valley (on the other side of the mountain from Grindelwald). They are about 25 mins away (car) or an hour (train) apart. People typically prefer one or the other but they are just different areas. I LOVE the hike from Grindelwald, past the Berghotel Grosse Scheidegg, through Scwarzalp, to Rosenlaui. The view you have throughout the hike is the best there is and it is a low-altitude hike to-boot!

Luzern is another great place to go where you can stay on the Vierwaldstaettersee, take boats out to other mountains, and cogwheels and cable cars to their tops. A spectacular region and opportunity!

Appenzell is not to be missed and the food and hiking combined with the scenery and even-tempered weather make it hard to beat.

Saas Fee is better than Zermatt (not going to argue this with anybody, but it is my strongly held opinion) and just one valley over in the Saastal. Also car-free, with a place to park your car right outside the town but up in the mountains unlike Taesch, just different.

I would choose one and go. Spend all 4 days there and do a day-trip or two (or 3 if you are in Luzern!) while you are there.