During the age of dinosaurs, surface water temperatures at the equator were likely around 30°C (86°F) year-round. According to Britannica, this was calculated using oxygen isotope measurements of calcitic remains of marine organisms. Early Aptian tropical sea surface temperatures (SSTs) were estimated to be between 27-32°C, and tropical SSTs during the late Albian most likely averaged around 30°C.
And now...
Surface water temperatures at the equator are generally warmer than at higher latitudes due to the sun's direct rays at the equator. The average surface water temperature at the equator can range from around 26-30°C (79-86°F). These warmer temperatures near the equator significantly impact global climate patterns and weather, according to NASA Earth Observatory.
