The water temperature in Mexico can vary depending on the region and time of year. In general, the water temperature ranges from around 21-29°C (70-85°F) throughout the year.
In the Sea of Cortez, the water temperature tends to be warmer and ranges from around 24-29°C (75-85°F) from May to November, while in the winter months, it can drop to around 65-70°F (18-21°C). On the other hand, the water around the Socorro Islands tends to be cooler, ranging from around 21-26°C (70-78°F) in the winter months from November to April, and around 26-28°C (78-82°F) from May to October.
It's important to bring the appropriate wetsuit to ensure you stay warm and comfortable while diving. A full wetsuit is recommended for most diving in Mexico. In the cooler months, a 5mm or 7mm wetsuit with a hood may be necessary, while in the warmer months, a 3mm or 5mm wetsuit may be sufficient. It's also important to consider any additional layers, such as a rash guard or dive skin, to protect against the sun and provide extra warmth. Be sure to check with your dive operator for their specific recommendations based on the time of year and diving conditions