San Diego Water Temperature by Month: When to Dive Dry

San Diego has a reputation for sunshine, but its ocean is cool all year. Knowing what the water will be, at the surface and at depth, decides what you wear and how much you enjoy the dive.

Average water temperature by month

These are long-term average surface temperatures measured at Scripps Pier in La Jolla, from NOAA's Coastal Water Temperature Guide, as compiled by Current Results.

Where a range appears, the average shifts between the first and second half of the month. Any single year can run warmer or colder than these averages.

Is it colder at depth?

Often, yes. In summer, the sun warms the surface layer, and a thermocline separates it from colder water below. You can descend through it and feel the temperature drop by several degrees within a few feet.

The local site Divebums describes summer water at depth from the low 60s to the high 60s, sometimes into the low 50s, and winter water at depth from the very low 50s to the high 50s, occasionally 49°F. Plan your exposure for the bottom of the dive, not the top.

When should you dive dry?

There's no single cut-off, but these are the situations where a drysuit makes the biggest difference:

• Winter and spring, when the water is in the 50s.
• Long dives, where cold builds up over time.
• Deep dives, below the thermocline and where a wetsuit compresses and loses insulation.
• Repetitive dives and training days, when you're in and out of the water for hours.

Many San Diego divers dive dry all year. Others use a 6 or 7 mm wetsuit with a hood and thick gloves in summer. Being cold costs more than comfort: it makes you breathe harder, and it makes fine control harder.

What changes when you switch to a drysuit?

Buoyancy, weighting and trim. A drysuit holds a bubble of gas that moves to the highest point, and its undergarments usually mean more lead. Redo your weight check whenever you change suits or undergarments, and learn the emergency skills before you need them. See Drysuit Buoyancy and Trim.

A drysuit also changes your options for heavier rigs. UTD's steel-doubles rule calls for a balanced exposure system, with an exception for cylinders neutral or positive at 500 psi/35 bar. Gardner's stricter local policy does not pair steel cylinders with wetsuits.

Stay warm, stay sharp

UTD's drysuit course recommends electric heating, and a heated vest under a drysuit makes a long training day far more comfortable. Whatever you wear, plan for the coldest part of the dive and the full exposure. Select a thermal system and dive plan that remain manageable if heating fails; heating does not replace insulation or the agreed exit plan.

Learn to dive dry

Our Drysuit Diver course covers drysuit buoyancy, emergency procedures and suit care. For where to dive once you're warm, see DIR and Technical Diving in San Diego and La Jolla Shores for Skills Practice.