CET is UTC+1 as summer time is called CEST. It's similar to the US Daylight Savings Time (DST) which in abbreviated form is written out as a single "D" which replaces the singular "S". So Eastern DST is written as EDT while winter time AKA "standard time" is written EST. The reason for why it is called "standard time" is that summer time/DST hasn't been around for that long, only since April 30 1916 in Germany for example. So for the longest amount of time, there was only winter time/standard time.