Lake temperatures

This photo from the Finnish meteorological website which measures lake temperatures throughout the country shows that in the coming days, a good number of lakes especially in the southern half of the country will see their water temperature exceed 25C.
That's an extremely unusual situation - I've only seen it rarely in all the time we have been here, and for us personally it has only been like this in 2010 and 2011. These are generalisations - in smaller lakes such as our one, the temperature may even be higher!