Data from Copernicus Climate Change Service (C3S) of the European Centre for Medium-Range Weather Forecasts (ECMWF) has confirmed that 2023 was the warmest ever year on record and by a big margin. Other global temperature datasets are almost certain to confirm this trend, too. This was accompanied with another worrying trend in 2023: the highest recorded sea surface temperatures (SSTs). This is important because sea temperature is among the big drivers of global climate. Warmer oceans lead to more water vapour in the atmosphere, which feeds weather events such as rainfall, snowfall, and cyclones. It is obvious that big changes in SST will also affect the survival and migration patterns of marine life, which ultimately affects human life too. Here are four charts that describe SST trends in 2023.