Projekt Runeberg has some useful historical climate data in the "Sweden : historical and statistical handbook" 1914, English version.
http://runeberg.org/sweden14/1/0061.html"Of the whole area of Sweden, 65 000 sq. km or about 15 %, are situated
north of the Arctic Circle, ... "
Lying as it does across the Arctic circle, Sweden offers an insight into the way in which Arctic sea ice loss has affected climate in Scandinavia.
The section on climate lists mean temperatures as of 1914 together with mean isotherms for the period 1860 - 1898.
The descriptions of ice and snow cover might be of use in showing how the Arctic and sub-Arctic climate has changed.
I hope this resource may be of interest to Neven's Arcticians.
