How to check:
- List the release dates for the past year or two.
- For each, record GBPUSD's move in the first 15 minutes and the range of the London morning compared with nearby days.
- Note the surprise against forecasts.
A middle approach: no trades from 06:58 to 07:05 London on release days, then normal trading, unless the surprise was large.
Why it matters for London scalpers specifically: the 07:00 release happens before the London open, so its effect can shape the first hour. A big surprise can make the 08:00 open move further than usual.
Do you treat monthly GDP as a major release?