From 51.5°N: best February to April, peaking at 60° at 22:00.
- JanJanuary: 37 degrees at 22:00
- FebFebruary: 54 degrees at 22:00
- MarMarch: 60 degrees at 22:00
- AprApril: 51 degrees at 22:00
- MayMay: 34 degrees at 22:00
- JunJune: 16 degrees at 22:00
- JulJuly: -1 degrees at 22:00
- AugAugust: -13 degrees at 22:00
- SepSeptember: -17 degrees at 22:00
- OctOctober: -12 degrees at 22:00
- NovNovember: 1 degrees at 22:00
- DecDecember: 18 degrees at 22:00
Altitude at 22:00 local time on the 15th of each month. Twilight, moon and weather are your problem.