‘…the year itself is not divided by [the Germani] into as many seasons as it is with

us [Romans]: winter, spring, and summer are the seasons they understand and have

names for; the name of autumn is as completely unknown to them as are the bless-

ings that it can bring’

Tacitus, De Germania, late 1st Century A.D.

Even though most prechristian seasonal celebrations, rituals and habits have died out, there are still some traditions that can be seen as ancient and pagan. Among those are field processions, midwinter celebrations of giving gifts,  decorating homes and temples with greenery during several seasonal feasts, decorating (May)trees and lighting fires at summer festivals. The celebrations may not be exactly the same as they were and may have different motifs (i.e. christian and in a modern context instead of ancient and pagan), but the blueprint of what we do now was definitely there already in pagan times.

 

For an intesting insight about how the seasons might have been marked and celebrated, read this article about the solar observatory in Tiel.