During winter, the surface water temperature of the Pacific Ocean is generally cooler than in summer due to reduced solar radiation and increased heat loss to the atmosphere. In the North Pacific, the winter surface water temperature can drop to around 5-10 degrees Celsius (41-50 degrees Fahrenheit) in the northernmost regions, while in the South Pacific, the winter surface water temperature can drop to around 15-20 degrees Celsius (59-68 degrees Fahrenheit) in the southernmost regions.
However, it's important to note that the Pacific Ocean is a vast body of water, and the temperature can vary significantly depending on factors such as ocean currents, depth, and local weather conditions.