Cold Water Adaptation: Wetsuit Thickness for Fall Spearfishing in SoCal
Fall brings some of the best spearfishing conditions to San Diego waters, but it also brings the cold. Water temperatures drop steadily from September through November, and choosing the right wetsuit thickness isn’t just about comfort—it directly impacts your bottom time, mobility, and safety. Here’s what you need to know to stay warm and hunt effectively.
Water Temperature Timeline for San Diego Spearfishing
San Diego’s water temperature follows a predictable seasonal pattern. In September, you’re still in the mid-60s (°F), but by mid-October, we’re dropping into the low 60s. By November and December, expect 58–62°F at the surface, with deeper zones running even colder. This matters because your choice of wetsuit thickness determines how long you can effectively hunt before hypothermia risk climbs.
Check the Element app regularly—water temps change week to week, and early fall can still support thinner suits on warmer days at spots like Sunset Cliffs or Crystal Pier.
Wetsuit Thickness Breakdown
5mm Suits (September) Early fall at spots like Pacific Beach and Mission Beach still tolerates a 5mm for short sessions. A 5mm full suit gives you mobility for finning and gun handling, but you’re limited to 60–90 minutes before cold starts affecting performance. 5mm works if you’re hunting shallow reefs in the first half of September, but plan for a transition.
7mm Suits (October–Early November) This is your workhorse. A 7mm full suit with a hood is the standard for most San Diego spearos from mid-October through early November. The 7mm provides solid insulation while maintaining the flexibility you need for precise aim and movement through kelp. You’ll comfortably handle 2–3 hour sessions at La Jolla Cove, the Coronado Islands, or deeper reefs off Ocean Beach.
A 7mm hooded suit is non-negotiable—heat loss through the head accounts for up to 40% of total body heat loss, and a hood makes the difference between a productive hunt and an uncomfortable shiver fest.
8mm and Thicker (Late November–December) By late November, water temps dip into the upper 50s. An 8mm full suit, preferably with a hood and booties, becomes essential if you’re planning extended bottom time. Some hunters opt for 7mm + 3mm vest combinations for added torso protection without sacrificing leg mobility. The vest approach works well for deep hunting where you’re not finning as much.
If you’re hunting through December or early January, consider a 9mm or even a 10mm hooded suit for extreme cold tolerance. Yes, mobility takes a hit, but so does hypothermia risk.
Fit and Sealing Matter More Than Thickness Alone
A loose 7mm suit will chill you faster than a properly fitted 5mm. Water floods into gaps and flushes warm water out constantly. Make sure your suit seals at the neck, wrists, and ankles. Look for suits with chest zips or back zips that minimize water entry. Brands like Xcel and O’Neill make quality spearfishing-specific suits that don’t restrict arm movement needed for gun handling.
Booties are essential year-round in San Diego—rocky reefs at Windansea, Bird Rock, and the Coronado Islands will shred unprotected feet, and they add insulation too.
Depth and Duration Considerations
Shallow reef hunting (15–30 feet) at spots like Torrey Pines State Natural Reserve or Bird Rock warms up faster in early fall, so you can get away with lighter suits. Deep hunting (40+ feet) off Ocean Beach or the kelp forest zones around La Jolla requires thicker protection because water stays colder and bottom time extends.
Plan your suit choice around your intended depth and hunt duration, not just the calendar. A 45-minute shallow hunt in mid-October might work in 5mm; a 2-hour deep hunt needs 7mm minimum.
Transition Strategy
Rather than guessing, use the Element app to track weekly water temps. Here’s a practical timeline:
- September: Start with 5mm; switch to 7mm by mid-month
- October: 7mm hooded suit is standard
- November: 7mm hood or 8mm depending on sensitivity; consider booties
- December+: 8–9mm hooded, booties mandatory
Don’t Neglect the Basics
Thickness is only part of the equation. Proper hydration, a warm meal before diving, and gradual cold water exposure over weeks (not a sudden plunge into December conditions) help your body acclimate. Spearfishing demands focus and precision—cold water dulls both. A properly insulated hunter is a safer, more effective hunter.
Keep tabs on conditions with the Element app to dial in the exact moment water temps shift in your favorite hunting zones. It’ll save you from showing up in the wrong suit.