here you go :) Sommer = derived from the old nordic word sumar, and means "half year" Vinter = an old nordic word which stems from the old gothic word Wintrus, and means wet season Vår = the word used in the past for forår, it stems form the old nordic word "vár" which meant "the good season" høst (harvest) = the word used in the past for efterår, an old nordic word which meant "to pick", since autumn was the season of harvest

forår = derived form the medieval german word "vorjar", "vorjar" means "first part of the year" efterår = was simply formed in opposition to "forår"

Den Danske Ordbog giver en kort forklaring på oprindelsen af "forår":

http://ordnet.dk/ddo/ordbog?query=for%C3%A5r Forår efter middelnedertysk vorjar, første led vor i betydningen 'første del af'

In dutch we use both lente (=spring) and voorjaar (before year) for spring. And we use herfst (autumn) and najaar (after year) for autumn. So Forår and efterår were quite easy to remember for me.