Guide
Fajr and Isha at High Latitudes: The Twilight Problem
In cities far from the equator — think Stockholm, Oslo or Helsinki — summer nights are so short that the sun never dips far enough below the horizon for true twilight to end. When that happens, Fajr and Isha have no natural astronomical time, and they must be estimated.
Why it happens
Fajr and Isha are defined by the sun reaching a depression angle (around 15–18°) below the horizon. Above roughly 48–49° latitude, there are weeks in summer when the sun never gets that low — twilight lingers all night. The standard calculation simply has no answer, so a rule is applied instead.
The common solutions
- Middle of the night — split the time between sunset and sunrise; Isha and Fajr are placed relative to that midpoint.
- One-seventh of the night — divide the night into sevenths and assign Isha and Fajr accordingly.
- Angle-based — scale the twilight period by the ratio of the method's angle, giving a smoother result near the poles.
- Nearest latitude / nearest day — borrow the twilight timing from the closest latitude (or date) where real night does occur.
What MawaqitGo does
For high-latitude cities MawaqitGo applies the angle-based twilight rule (and the middle-of-the-night rule elsewhere), so Fajr and Isha always resolve to a sensible time. Your local mosque may follow a different convention — when in doubt, follow your community.