Key patterns to plan for:

• Currents and drifts: common in South Florida. Confirm pickup procedures, stay with your group, and carry an SMB.
• Surf and swell: a major factor for California and Hawaii shore entries. If the entry looks questionable, do not force it.
• Cold water: California, Monterey, lakes, and many winter months require more exposure protection and shorter surface intervals in wind.
• Boat traffic: always assume boats are present. Follow local diver-down flag rules, surface slowly, and stay close to your float or guide.
• Overhead environments: springs and caverns can be deceptively tempting. Only enter overhead zones with proper training, redundant gear, and a qualified plan.
• Altitude diving: treat mountain lakes as a specialty. Use altitude-capable dive computers or altitude tables and keep profiles conservative.

As a baseline, follow your training limits, do a real pre-dive check, and build wide safety margins when visibility or conditions are changing.

The U.S. has broad emergency medical coverage in populated coastal regions, but response time and chamber access can still vary by location.

• Call 911 for urgent emergencies.
• For suspected DCS or any dive-related medical question, contact DAN and follow their guidance while arranging transport.
• Know the closest recompression chamber to your dive region before you enter the water, especially for islands and remote parks.

If you are doing repetitive days, prioritize sleep, hydration, and conservative profiles, and plan your last dive to respect no-fly guidance.