First Day of Summer

First Day of Summer
Official name	sumardagurinn fyrsti
Observed by	Iceland
Date	first Thursday after 18 April
2016 date	21 April
2017 date	20 April
2018 date	19 April
2019 date	25 April
Frequency	annual

The First Day of Summer (sumardagurinn fyrsti) is an annual public holiday in Iceland held on the first Thursday after 18 April. In former times, the Icelanders used the Old Norse calendar which divided the year into only two seasons, winter and summer. Although the climate in late April cannot be considered to be summer-like, after the long winter, Icelanders still celebrate this first day of "summer" with parades, sporting events and organized entertainment, held in various places around Iceland.

...
Wikipedia