Trosa Sea Temperature
The water will feel freezing / baltic. You would have to be insane or getting paid to want to get in water this cold! If you do make sure you are wearing a top end drysuit and all the accessories.
The measurements for the water temperature in Trosa, Södermanland are provided by the daily satellite readings provided by the NOAA. The temperatures given are the sea surface temperature (SST) which is most relevant to recreational users.
Water temp by month
Monthly average max / min water temperatures
The graph below shows the range of monthly Trosa water temperature derived from many years of historical sea surface temperature data.
The warmest water temperature is in August with an average around 65.7°F / 18.7°C. The coldest month is February with an average water temperature of 33.8°F / 1.0°C.