Since the demise of scottishclimbs.com as an active website, some of the wiki information is being migrated to here to keep it "live" the following 3 areas are works in progress.
Sheigra is a beautiful coastal venue in the far NW of Scotland, just south of Durness. It is known for its fantastic trad climbing on Lewisian Gneiss, but there has been considerable bouldering development, both on the Gneiss and the conglomerate found in the area. A topo has been produced, see this thread.
Snows and bitter cold in higher areas, but often excellent conditions by the coast when it's not raining.
Often great conditions everywhere, although depending on the winter a lot of the higher stuff can be snowbound. The East Coast can get the sea fog (haar) in for a few day (or occasionally weeks") at a time, leaving eveything on the coast damp, while a few miles inland can be clear skies.
Time of the dreaded midge. Can drive you insane in summertime, but worth knowing their limitations. Midge squadrons are grounded and unable to fly in the following conditions:
And they are not fond of bright light.
So if you make your choices well - exposed spots on sunny days you can get things done even in midsummer. However, camping can be terrible even if the day has been fine, so consider bunkhouses, B & Bs, Cottages or getting into the Pub.
They are also much less of a hassle on the East Coast, but can still be found on still overcast days in the evening.
A midgie net is a worthwhile investment, as well as a repellent method, with may or may not work.
Cooler, dry days can often bring the best bouldering conditions in Scotland, but it can be very wet too.
In essence, any time of year can either be brilliant or totally pants.
All the recent SMC Guides have a bit on bouldering in the respective area guides, mostly text based and utilising a combination of Font Grades for harder probs and UK technical grades for easier stuff.
Stone Country Guides
John Watson's Stone Country Publications has produced a "Bouldering in Scotland" Guidebook, as well as several useful in depth downloadable guides to some areas.
Locally Produced Mini Guides
There are several locally published mini guides, including Ullapool Area, Skye, Glen Nevis and Portlethen. Availability is variable to say the least, so best enquire before visiting an area rather than hoping to pick something up when you get there.
Another site from John Watson is Boulder Scotland.
Word of Mouth
Bouldering in Scotland is still in its infancy, with relatively few folk dedicated to the cause, so it is worth asking around and you may (or may not!) get information on developing local venues. Also keep your eyes open wherever you may be and you might just find something.