In reply to Logoir:
I have a base on Skye and I can confidently say that you have no chance of guaranteeing good weather. But late April to late May gives the best likelihood probably with the emphasis on the early weeks. Midges can be an issue in late May but only rarely.
Visit the Cuillin above all. They offer a little bit of Norway close to home. But be sure to visit each of the peninsulas for a varied taste of Skye's amazing riches. Suggestions:
Trotternish
Explore the Sanctuary and the Old Man of Storr or follow in the footsteps of the Victorians wandering through the pinnacles of the Quiraing. Best on a misty day. Drive back westwards over the road to Uig, stop at the pass for the most extensive view in all Scotland. You can see from Mull right up to Cape Wrath.
Waternish
Do the circuit of Beinn an Sguirr for a good tramp with great views then visit Stein, a quiet fishing community for a day of peace and calm.
Strath and Minginish
Take the boat from Elgol into Coruisk and climb Sgurr na Stri or Sgurr Hain before walking all the way back to Elgol. Definitely 6 rather than 4 hours but not to be missed. On a second day climb Marsco from Sligachan (very steep) or Loch Ainort (much easier) for the best view of the black Cuillin from a point set back from the range.
Duirinish
Wander the spectcular cliffs of Waterstein Head and the Hoe before a short drive to Neist Point for great seaward views, especially at sunset. Whales and basking sharks if you are lucky. Seals guaranteed.
Sleat
Sleat has no natural wonders of its own yet this is the prettiest part of the island, especially in late May with abundant wildflowers. What Sleat offers, and utterly unique in the UK, is a lush platform from which to admire the stupendous wall of the rugged Knoydart mountains tumbling precipitously into the Atlantic. In winter, this feels as close to Alaska as you can find in Britain. In summer, visit Eilean Iarmain (Isle Ornsay) for the classic view of moutains soaring above the lighthouse, then pop down to Armadale and do the charming headland walk in the woods (with otter hide and plenty of seals) signposted behind the shop at the ferry terminal.
Post edited at 17:56