I assume that TOS means ThinkOrSwim?
You will find quite a bit of variation, from one broker to the next, in the time that Daily candles open and close. But, most of that variation occurs between 5pm and midnight New York time (10pm-5am, London time).
The opening/closing time for Daily candles affects candles on all timeframes from 2-hour through Daily.
Candles on timeframes from 1-minute through 1-hour are not affected, regardless of when Daily candles open and close.
And candles on Weekly and Monthly timeframes are also not affected by the Daily opening/closing time.
Well, it’s preferred by many traders, including me. And this has nothing to do with the fact that I’m an American, or that I live on the U.S. east coast. It has to do with the natural, daily ebb and flow of worldwide forex trading volume. Generally, total world trading volume is at its lowest level of the 24-hour day between 5pm and 6pm New York time. This pattern repeats daily (with occasional exceptions).
At 5pm New York time, the [B]normal business day[/B] has ended, or is ending, in the 3 largest forex markets — central Europe (which is all one time zone), London (the world’s largest forex market), and New York (which accounts for the vast majority of forex trading throughout North America).
Furthermore, at 5pm New York time, the normal business day has not yet begun in the major forex markets of Tokyo, Hong Kong and Singapore.
Only New Zealand and Australia are open in the hour between 5pm and 6pm New York time, and those two markets combined account for only 4% of total worldwide forex trading volume.
2359 hours [I]where?[/I] Would every broker around the world set their platform to open a new daily candle at midnight, local time? There are nominally 24 time zones around the world. So, except for the time zones in the Atlantic and Pacific oceans, you would have about 16 different time zones where local forex brokers would be setting their platforms to open/close at midnight, local time. That situation would be even crazier than the situation we presently have.
Brokers lease the MT4 platform from the Russian developer, and it comes defaulted to whatever open/close time the developer has built into it. A few years ago, I saw an MT4 tutorial video (from Alpari-UK, I believe) in which they explained, in detail, why they opened and closed daily candles at 10pm Central European Time. At that time, it was possible for individual brokers to re-configure their MT4’s to open/close at a different time, but most brokers didn’t bother.
I’m not an MT4 user, so I don’t know whether things are different now.
Correction:
The Alpari video mentioned above explains that MT4 daily candles open and close at MIDNIGHT Central European Time, not 10pm as I stated above. Central European Time is the time zone in Paris, Frankfurt, Zurich, Stockholm, Berlin, etc.
Midnight Central European Time is 11pm London time, and 6pm New York time.
The Alpari MT4 video is still hosted on YouTube; so, I presume that means that the information it contains is still current.
Here’s a link — Tutorial 1 - MetaTrader 4 Tips and Tricks - YouTube.
Scroll to about 2:00min in the video, for the explanation I referred to.