Tonight we change our clocks moving the clocks one hour forward. One way to remember this is Spring Forward / Fall Back. In the Spring we set clocks forward one hour. In the Fall we set clocks back one hour. So if you go to bed tonight at 8 pm and you get up at 7 am tomorrow, you will get one hour less sleep than you did with these sleep and wake times yesterday.
I used this site to find out that Tanzania does not have Daylight Saving Time. I did a search for China and learned that they don’t do this in China as well. Please see the above map and see which countries use a Daylight Saving Time system. The green areas are using a Daylight Saving Time. The Blue ones used it in the past but don’t any longer. The White areas indicate places that have never used a Daylight Saving Time system.
Are you interested in where this time change thing started? Here is a internet site that gives good information about this.