Yup. — You’ve got a nuisance to contend with here.
Before we go any further, consider this. If the London open is critical to the back-testing you want to do, you might want to search for a UK broker who offers an MT4 demo account which remains on London time throughout the year. Then, you can do your back-testing on that platform without worrying about time changes, and do your trading wherever you prefer.
If that’s not a viable solution to your problem, then you’ll just have to make a bunch of adjustments back and forth between 10am and 11am for [I][B]your[/B][/I] London open candle, over the course of your back-test period. I don’t know how far back you want to go with this back-testing, so I’ll just take a guess that 3 years will get you started.
Going back 3 years, here are the dates that affect your back-testing [B](all dates are Sundays):[/B]
Spring 2012
March 11, 2012 — the US began DST — on your platform, the London open changed to 11am
March 25, 2012 — the UK began DST — on your platform, the London open changed to 10am
Fall 2012
October 28, 2012 — the UK returned to standard time — the London open changed to 11am
November 4, 2012 — the US returned to standard time — the London open changed to 10am
Spring 2013
March 10, 2013 — the US began DST — on your platform, the London open changed to 11am
March 31, 2013 — the UK began DST — on your platform, the London open changed to 10am
Fall 2013
October 27, 2013 — the UK returned to standard time — the London open changed to 11am
November 3, 2013 — the US returned to standard time — the London open changed to 10am
Spring 2014
March 9, 2014 — the US began DST — on your platform, the London open changed to 11am
March 30, 2014 — the UK began DST — on your platform, the London open changed to 10am
Fall 2014
October 26, 2014 — the UK returned to standard time — the London open changed to 11am
November 2, 2014 — the US returned to standard time — the London open changed to 10am
Spring 2015
March 8, 2015 — the US began DST — on your platform, the London open changed to 11am
March 29, 2015 — the UK began DST — on your platform, the London open changed to 10am
Fall 2015
October 25, 2015 — the UK will return to standard time — the London open will change to 11am
November 1, 2015 — the US will return to standard time — the London open will change to 10am
No doubt, you see the pattern above. So, going forward into 2016, etc., all you will need is the time-change dates for the US and the UK, and the template above.
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