There are a few ways you can make life very easy for yourself when using a time zone maps:
Firstly, you’re looking at a map of the world, so the first thing to do is identify the locations you are interested in knowing the times for on the map.
Secondly, find a place on the map where you know the time. Either the place you are currently at or another location you are familiar with. The Prime Meridian is generally a good measuring stick for determining time zones given its +0 in UTC.
Now you just work out the difference between them in hours. There may be several locations, but the method is the same: count the number of time zones between them. Put a finger on the time zone you know: if you have to move left, then subtract from your starting number. If you have to move right, you will add to your starting number. Whatever number you are left on is how many hours ahead or behind the other location is. You can even do this to compare to places you don’t know.
For example, if you know that the time is 7am on the east coast of the USA and you want to know the time on the west coast of Africa, simply count the time zones between them. You must move five time zones to the right to reach the west coast of Africa, 7+5=12, therefore it must be noon there.
Let’s keep using this example. So it’s 7AM on the US East Coast, and Noon on the West Coast of Africa, but you are trying to coordinate 3 time zones and one of them is in Berlin as well. You only have to go right once, so it would be 1PM in Berlin, or Continental Time depending on who you ask, whilst it’s noon in West Africa and 7AM on the US East Coast. You can repeat this method as many times as you need.
The next thing to consider then is travel times: say you are travelling from the US East Coast to the African West Coast and the flight takes 5 hours. It will be 5PM at the destination, since you would add the hours from changing timezone to the length of the journey. So this same method can give you a general idea of the degree of jetlag you are likely to feel if planning a trip as well.
Even outside of travel and business, it is just good to keep in touch with friends and family around the world, and a time zone map is a quick and simple way of making sure that it’s always possible to sync up times.