Greenwich Mean Time (GMT) is used in Ghana year-round, and there are no seasonal time changes. For example, when it's noon in Accra, it is 7 am in Washington, DC/ Ottawa, Canada during the fall and winter months, but 8:00 am during the spring and summer. Because of Ghana's close proximity to the equator – only a few degrees above it - sunrise and sunset times do not vary much throughout the year. In Accra, on average, the sunrise is at 6 am and the sun sets at 6:15 pm with only slight variations depending upon the time of year. The dry season brings days with slightly more daylight and the wet season has slightly less.
Ghana national holidays:
January 1 New Year's Day
March 6 Independence Day
(Variable) Good Friday
(Variable) Easter
(Variable) Easter Monday
May 1 May Day
May 25 African Unity Day
July 1 Republic Day
September 21 Founders Day
1st Friday in December Farmer's Day
December 25 Christmas
December 26 Boxing Day
The two official Muslim holidays, Eid El Adha and Eid El Fitr (at the close of Ramadan), are determined by the lunar calendar, so the dates vary from year to year. Other holidays may be announced with relatively short notice.
One thing you'll encounter while in Ghana is that most Ghanaians move to their own beat, so to speak. Lateness is a way of life, and readily accepted. Meeting times, appointments, bus departures etc., none of them will begin at the scheduled time. You will either "deal with it" or let your Ghanaian friends know that tardiness is something you can't abide with – then stick with your principles. Sooner or later, they'll catch on.