Day and night limits
The beginning of morning civil twilight and the end of evening civil twilight are expressed in local time and are applicable throughout FIR Switzerland. The reference point for time calculation is Bern observatory. Morning civil twilight begins and evening civil twilight ends when the center of the sun's disc is 6° below the astronomical horizon and lasts a little more than 30 minutes.
Sunrise (SR) corresponds with the end of the morning civil twilight (HR* +30 MIN) and sunset (SS) with the beginning of the evening civil twilight (HR* -30 MIN).
Summer time (ETE; UTC+2) comes into force on the last Sunday of March. Summer time ends on the last Sunday of October.
See AIP Switzerland GEN 2.7 -1 and VFR Manual Switzerland RAC1-1 + VFR COR