In reply to ADJC:
In order normally the worst months are:
July
August
June
September
May
Outside these months it is unusual you'd find any/many midgies and if you did they wouldn't normally be that annoying.
Generally midgies are not really annoying until at least mid may, they continue being bad until either a very long dry spell or the first set of frosty mornings.
During the very hot dry summer 2 years ago many people were reporting virtually no problem with midgies even on Skye!