There's a recently deployed online service that gives a "Midge forecast" for Scotland. The midge is a tiny creature that at certain times of the year, and in certain conditions, rises from the ground in swarms and can give irritating bits.
Okay, some limitations. Mainly, that this online service is primarily to promote a midge obliteration machine that is being sold by the sponsors of the website.
The other main limitation is that there are many different kinds of midges. Different kinds bite different people. For example, I'm relatively unaffected by the Berneray midges, but have been bitten half to death by the midges on the north east side of Barra. The reverse will happen for other people. It makes a bit of a nonsense on the forecast to say "Stornaway 1" (spelling the town name incorrectly) when some folk will be affected, and others not, by the different kinds of midge in the Stornoway area.
Also, the best forecast for midges is the weather forecast. The nippers tend to come out when its overcast, a bit damp in the air, and its very still. The one thing they can't handle is wind; one breeze and they're gone.