Hi Grace-
In all cases, visits to mountaintops are best if the weather is clear up top. It does come in layers, especially in Winter, as the attached image shows, so check webcams and local information sources before heading up. It may be cloudy or hazy in the valleys and clear at higher elevations. However, March can be cloudy, in general, so mountain top viewing may be poor. The best way to make that work is to try to schedule several days in an area. The weather in the Alps can and does change frequently, with poor ability to forecast in detail, even 24-48 hours ahead. On a cloudy and foggy day in mid-June, in Wengen, we had a sudden window of sunny skies for about 4 hours, that was not forecast. Then, the clouds rolled back in.
Also, the cograil access to Pilatus does not run in the Winter, and usually does not restart until about May, if I recall correctly:
http://www.myswissalps.com/pi latus
specifically:
http://www.myswissalps.com/pi latus/gettingthere.
So, you’d have to take the cableway from Kriens.
In general terms, as 1960man pointed out, the trail conditions are highly dependent on altitude, during most seasons, perhaps with the exception of July through September. So, if you are looking for nice walks or hikes, perhaps you could look at lake shores. Many major Swiss lakes are at around 400 meters altitude, which will often be snow free in late March. And, early April is even better. Some lakes have very steep shores, and the trails may be higher, and some lakes are also a bit higher. (The Thunersee and Brienzersee are at about 560 meters elevation) .
However, in contrast, trails at Männlichen ( at about 2230 meters) , above Wengen, are impassable well into June in most years.
The Lauterbrunnen Valley…. for example, from Stechelberg to Lauterrbrunnen is an easy walk, likely to be snow free, as Snowman noted for the more northern stretch to Wilderswil (at about 600 meters). The altitude is about 860 meters where the cableway from Mürren has its valley station in Stechelberg, and about 800 meters at Lauterbrunnen.
If you like maps, this one has altitudes, as well as a whole lot of (perhaps too much of) other information:
map.geo.admin.ch/?topic=swisstopo&lang=e n&bgLayer=ch.swisstopo .pixelkarte-farbe&catalogNodes=139 2,1538,1396,1430,1436& layers=ch.swisstopo.sw isstlm3d-wanderwege&E=2635904.0 0&N=1159957.00&zoom=7
This explains the types of trails, and the color coding:
http://www.schweizmobil.ch/en /wanderland/more-wl/hiking-trail-network-and-signalization.html
Yellow ones have the best trail conditions, although all trails may have hills.
Some lake shores get a lot of sun, and would have a better chance for nice walks. In particular, near Weggis and Vitznau on Lake Lucerne ( as well as other west facing shores of that lake) and the shore line near Montreux. Also la Cote Lavaux…vineyards.
http://www.myswissalps.com/hi king/lutry-epesses.
March does not generally have very good weather for outdoor activities (unless you ski) but there can be clear, warm days. They are hard to schedule, however. A benefit is low tourist density in March.
I have attached my favorite picture from the Emmental, taken on April 17th, in 2014, at about 760 meters above Sumiswald (700 meters), looking toward Trachselwald. In 2014, in mid April, there was a period of about 10-14 days of unusually warm, sunny and clear days throughout most of Switzerland. Spring came a bit early.
The image tells something about the seasons. The deciduous trees are blossoming, but no leaves are out yet. The grass is getting green in the very lowest elevations (at about 660 meters) , but not really in Sumiswald and farmers are plowing and planting. But, the Alps are fully snow-covered.
Are you locked in to March?
Slowpoke