The temperature of the ocean's surface layer, a key indicator of climate variability and air-sea heat exchange.Sea surface temperature (SST) is the temperature of the ocean's top few meters, the layer that directly exchanges heat, moisture, and gases with the atmosphere. It is a fundamental variable in climate science because the ocean stores and releases enormous amounts of heat, and SST determines how much energy flows into the air above. Even small changes in SST—fractions of a degree—can shift weather patterns, influence hurricane intensity, and alter marine ecosystems.
Systematic measurement of SST began in the 19th century with ship-based observations, but global satellite monitoring started in the late 1970s, revolutionizing the field. The concept of SST as a key climate indicator was formalized in the mid-20th century as ocean-atmosphere interactions became a focus of research.
SST is measured by satellites that detect infrared or microwave radiation from the ocean surface, as well as by buoys and ships that take direct readings. The ocean's surface temperature is set by the balance of incoming solar radiation, heat loss through evaporation and longwave radiation, and mixing with deeper waters. Because water has a high heat capacity, SST changes slowly compared to air temperature, making it a kind of 'memory' of past climate conditions that can influence weather weeks or months later.
SST data are used in weather forecasting, hurricane tracking, and climate models, as well as in fisheries management to predict shifts in fish populations and coral bleaching events.
The warmest SSTs on Earth occur in the western Pacific 'warm pool,' where temperatures can exceed 30°C (86°F), fueling some of the most intense thunderstorms on the planet.






















