When you open the page you see the current time in different cities and time zones on one screen. Use it to check the time difference before calling someone abroad or when planning an international meeting. You don't need to sign up, the tool works right in your browser.
Turkey uses the UTC+3 time zone all year round and does not observe daylight saving time.
Yes. In countries that observe daylight saving time, clocks move forward one hour for part of the year, so the difference between two cities can change during the year.
UTC is Coordinated Universal Time, the reference that time zones around the world are based on. Other times are expressed as plus or minus hours from UTC.
The tool is completely free and requires no account.