Valborgmässoafton, or 30th of April festival, is a day where students dress in funny costumes (most of the time) and ride fragile boats (that they make themselves, for the most part) on the Fyris river. This tradition happens every year no matter what weather it is.
Usually this happens during the morning hours, then at 3pm the students (new and old) meet at Carolina Rediviva to take off their white student hats and at night there are fires lit to celebrate and welcome the arrival of Spring.
If you travel in the beginning of the summer (around April), you have to see Valborg! Valborg is the student activity, the symbol of the beginning of summer.
The rector of the Uppsala University will throw his graduation cap, followed by hundreds and hundreds of graduates, from old to recent graduates.
You can enjoy the funny boat race, and the whole Uppsala will be crowding the city. And in the evening, there will be Champagne gallop in the student nations, followed by the big fire in Gamla Uppsala (Old Uppsala). The activity endures the whole day and night, since the next day is the labor day, when everything is closed.