The daily pattern
Spreads are widest at the weekly open, during the daily rollover window and in thin Asian hours. They are tightest and most stable through the London session and the London–New York overlap.
News-driven widening
Liquidity providers pull quotes seconds before major releases. Spreads can multiply several times over for a short period, which means a stop placed a few pips away can be triggered by the spread alone rather than by price.
Measuring it yourself
Add a spread column to your market watch and record the value at the times you actually place trades over two weeks. That personal sample is far more useful than any published average.
- Record spread at your usual entry times, not at random
- Note the value immediately before and after scheduled news
- Compare instruments at the same moment, never across days