The so called "Fifth Season" is the craziest time of the year. Carnival takes place on the weekend before the beginning of the Lent. If your calendar does not show the dates, look up the Easter date (which changes every year as it's the Sunday after the first full moon after the beginning of spring in the Northern hemisphere). Count back to the 7th Sunday before Easter, this is the main weekend.
People dress up, paint their faces, party, and drink. A lot. A LOT...
Children's party with my friends in 1972 (I am the little sailor)
For children, dressing up is the most important part. Girls want to be fairies or princesses or (since Harry Potter) witches, boys want to be indians or cowboys or policemen or (since Harry Potter) wizards.
When talking about carnival in Germany, people think about the "big 3" on the Rhine - Köln, Düsseldorf and Mainz. All other places in the region, and many others elsewhere, also have their carnival events.
November 11, St Martin's Day, is the official beginning of the 'campaign'. Jesters conquer the town halls and take over. The reign of the newly elected Carnival Prince and Princess begins.
Until after Christmas things then calm down, clubs and groups are busy with preparations. From late January they have their balls and indoor events. In the shows and speeches there is a lot of criticism concerning politics, society and whatever topic: sometimes funny, sometimes witty, sometimes just lame.
A week before Ash Wednesday the crazy days really start. Thursday is Weiberfastnacht , the day of the women.
The No. 1 day in the Rhinelands is Rosenmontag ("Rose Monday"), carnival Monday. This is when the big parades take place in the big centres. Smaller places in the surroundings often do their parades on Sunday or Tuesday so people can travel to one of the big cities on Monday.
On Aschermittwoch ("Ash Wednesday") everything is over. The Lent begins. A true catholic goes to church in the morning and receives a cross of ash drawn on his forehead.
Everything is over except some rare protesters, like the village of Kelze in the north of Hessen that celebrates its carnival on Ash Wednesday to annoy its neighbours: this is a Huguenot settlement surrounded by catholic villages...
This originally Bavarian term is widely used nowadays, mostly in regions that do not have a real carnival tradition but have imported the Rhineland type in recent decades.
The biggest parade in the whole of Northern Germany, for example, has been established in my hometown Braunschweig. This is a Rhenish import, founded by Rhinelanders who moved to Braunschweig and do just like at home.
On the other hand, there are new and individual inventions, like the Samba carnival parade in Bremen.
The Fastnacht in the South West (i. e. Black Forest, Schwaben, Bodensee and northern Switzerland), however, is much different from the carnival of the Rhine cities. Traditions are much older, in some towns masks and costumes have been the same for centuries. Fastnacht is the awakening of the dark powers - devils, ghosts, wild people, animals, and witches - before the beginning of the Lent, thus deeply connected to the catholic calendar (and not a remnant of pagan Germanic spring rituals, although people keep telling you that it is because they don't know that that interpretation derives from Nazi propaganda).
The Fastnacht guilds have one or a few figures that stay the same for years, decades, centuries. They don't change every year. Those costumes and wood-carved masks are hand-made, precious and beautiful to look at. There are a couple of places that keep centuries-old traditions alive, the best known among them is Rottweil. On the other hand, Fastnacht is a very lively, modern movement. New guilds are founded every year, new figures invented. More in my blog about the Alemannic Fastnacht!