Mokfest is always the weekend before the Cowal Games which itself is always the last Saturday of August.
So the 2015 festival will run from Thu 20th to Sun 23rd Aug.
This - I find - is the best way to work it out.
Some folk say it's the 3rd weekend of Aug but not so - as some years Aug has 5 weekends.
Another anomaly is when the last day of Aug is a Friday - Cowal would then be on Sat 25th and Mokfest as early as 16th to 19th.
To simplify - whatever the year - find the last Saturday of August then go for the weekend before.
Hope this makes sense.
'There Is A Light That Never Goes Out'