I'm on all day from 9h30-15h45, i dont take trades after 15h45 because it might not have enough time to complete and i dont want to have to close a position in the middle of a trade at 16h10 (i trade e-mini index futures)
When i was a newbie trader my gurus at the time would refer to lunch hour as being ''bad'' and low probability and everything. When we started designing our own system we ran stats on the trades between 11:30 and 1:30 to see is there was any truth to this, and something came out, over time trades on ''lunch hour'' are a bit less profitable, but they are nonetheless, and its worth taking them.
and i mean my trades in my system, you'll have to do the same work on your system or strategy to figure out if these trades are good or not. As a trader, you should be keeping a log or record of your trades with the time on it, paste that into excel and check in half hour segments. 11:30-12:30 was the ''worst'' part in the bunch for me.
Nonetheless, its generally recognized & accepted that it will move in the mornin' then calm down for lunch hour, then pick up in the afternoon.