May and June
Go nowThe longest days, and the city outdoors
The best window: warm without August's heat, light until late, and the parks, canals and beer gardens all in use. The city genuinely moves outside for these weeks. Prices have not reached the summer peak.
September
Go nowSummer warmth, fewer visitors, the season restarts
Warm days, cool evenings and the cultural season starting again after the summer break. The lakes are still swimmable early in the month. The best single month if you can only pick one.
July and August
Worth it, butHot, busy, and half the city is away
The warmest weeks and the most visitors, with the lakes and open-air events at their best. The cost is that Berliners leave: some restaurants and smaller venues close for the holidays, and the cultural institutions run lighter programmes.
April and October
Worth it, butCheap, changeable and perfectly workable
Shoulder months that swing between pleasant and grim with no warning. Prices drop noticeably and the museums, memorials and restaurants are entirely unaffected. Good value if the trip is indoors-weighted.
December
Worth it, butDark by four, with the markets as compensation
Cold and very short days, offset by Christmas markets across the city from late November. Almost everything shuts for two days around Christmas, including public transport running to a holiday timetable. New Year here is loud in a way that surprises people.
November
Think twiceThe greyest month, and the one before the markets
The bleakest window of the year: dark by mid-afternoon, wet, and with neither October's colour nor the Christmas markets, which only open in the last days of the month. Prices are at their lowest and the museums are empty. This is the one month that gives you almost nothing outdoors.
January, February and March
Think twiceGrey, cold and the least daylight of the year
The hardest stretch: cold, overcast for weeks at a time, and dark early. The prices are the lowest of the year and the museums, galleries and clubs all work perfectly — this is a legitimate Berlin trip if you plan it indoors. What you lose is the city's best feature, which is being outside in it.