May and June
Go nowBeer garden season starts, and nothing is full
The best window of the year: warm enough for the beer gardens and the English Garden, long days, everything open, and no festival crowd. This is Munich as it actually lives, and the Alps are at their best for a day out. Book normally; prices are ordinary and rooms are available.
July
Go nowWarmest, with the lakes in reach
The warmest month, with the beer gardens full every evening and the Bavarian lakes an easy train ride away. Summer thunderstorms are common and brief. German school holidays begin, which lifts prices somewhat, but nothing like the September peak. Excellent value for what you get.
September and October
Worth it, butOktoberfest: extraordinary, and the worst value of the year
The festival runs roughly the last two weeks of September into the first Sunday of October, and the dates move every year. Six million visitors, hotel rates several times normal, rooms gone months ahead. Come for it deliberately or avoid the window entirely. The rest of October, once it has packed up, is a lovely quiet autumn city.
December
Worth it, butChristmas markets, in cold and short days
The Christkindlmarkt on Marienplatz and a dozen smaller ones, mulled wine, and a city that does this properly. It is genuinely cold — Munich is colder than Berlin — and the days are short. Prices rise through the month. Worth it if the markets are the reason; not if you wanted to walk around.
August
Worth it, butHot, busy and the locals are away
Warm and full of visitors, with peak European holiday traffic and some smaller businesses closed while their owners are on holiday themselves. The beer gardens and the parks carry it, and the Alps are the escape. Fine, and a slight step down from July on price and atmosphere.
April
Worth it, butSpring arriving, unreliably
The city thaws, the gardens start opening and prices are low, but the weather is genuinely changeable and it can snow. Easter moves between late March and April and fills the city for a week. A gamble that often pays, with the museums as the fallback.
January, February, March and November
Think twiceCold, grey, and the outdoor city closed
Munich's winter is longer and colder than most of Germany's, and the beer gardens and parks — which are the point of this city — are shut or empty. The museums and the Christmas-free calm are real compensations, and prices are the lowest of the year. But you are visiting a different, smaller version of the place.