Daytime air temperatures in Estonia have been breaking the 30C mark this week as reported by ERR, as 2018's hot summer continues. However, sea water temperatures have fluctuated far more in recent days, even within the same location.

According to data from ilm.ee today, water temperature ranged from as low as 11C at Kakumäe and Pelgurand in Tallinn, to as high as 27C at Kuressaare, capital of the island of Saaremaa.

Water temperature at the seaside resort of Pärnu in south-western Estonia is recorded at just 15C today, with similar temperatures in the sea at the smaller resort town of Narva-Jõesuu in the northeast of the country.

It seems the warmest water temperatures so far as the sea is concerned have been recorded in the Haapsalu-Saaremaa-Vormsi triangle, possibly due to the shallower water in those areas as well as the sea being more enclosed in bays and inlets, than in other coastal areas.

Similarly high temperatures have also been recorded in freshwater locations such as Lake Peipus, whose north shore town of Alajõe posted a water temperature of 26C today, or at the Pedeli River in south Estonia (24C).

With Alajõe's air temperature being as high as 35C today, a dip in the water seems likely to offer little respite from the heat. Conversely, beach-goers in Vääna-Jõesuu to the west of Tallinn, whilst being thick in numbers since the weekend, have tended to steer clear of swimming due to the low water temperatures, and largely only paddled in the water; last week the water had been warmer and consequently seen more swimmers.

Red flags are used to denote low water temperature; another consideration putting some swimmers off, at least in the Tallinn area, may be reports of toxic cyanobacteria occurring in the area.