Let's start by saying, Fonna ski resort is not a great ski resort. Were it open during the winter it probably would not be very well visited. For that, the diversity of terrain and the lack of vertical drop is too limiting.
My overall review score reflects this too. No offpiste to speak of. Only one lift. And when I was there, so were many domestic and international ski teams. Cool to say that you saw the German ski team in their Bogner ski suits train on the same hill as you skied. Less cool to wait with them (and all the other teams) in what can be a very sizable lift-line at the bottom of the hill to wait to get up the single T-bar. The terrain that's open to the public is also quite limited as most of the hill is reserved for ski teams in training.

All of that said, Fonna is a great spot to go skiing in the summer. You ski some, you enjoy the spectacular views of the Hardanger fjord, you enjoy what's hopefully sunny weather, and you marvel at the fact that it's in the middle of the summer and you're still able to get some turns in on what's still quite decent snow (given the circumstances anyway). Although the vertical drop is fairly short, the hill is actually quite steep offering some great turns and you can definitely work up a heart-rate racing to the bottom. There is a reason all those ski teams train here after all.
And if you're up for a hike, take the lift up to the top and you'll have amazing touring options available across the Folgefonna glacier. The Fonna restaurant at the bottom of the hill is well worth a visit. Make sure you try the Norwegian waffle with sour cream and strawberry jelly.
I was there on June 24th, the longest day of the year and the weather was spectacular. In three hours of skiing I managed to get in four runs, mostly due to the said lift line at the bottom. But it really didn't matter. My friend and I had a great time and I'll definitely be back next time I'm in Norway during the summer and I have skis available.
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