Oct 23, 2026 HST
Next expected arrivals: about Nov. 2–4 and Dec. 2–4, 2026. Box jellyfish typically wash in 8 to 10 days after a full moon. With full moons on Oct. 25 and Nov. 24 (Hawaiʻi time), the next windows fall in early November and early December. These are estimates, so check lifeguard warnings before swimming.
If you’re stung
Get out of the water and tell a lifeguard. Rinse with vinegar if available, remove tentacles carefully, and seek medical help for severe pain, breathing trouble or an allergic reaction.
Earlier updates and background
The monthly pattern, tied to the lunar cycle, is well documented on Oʻahu’s south shore, where lifeguards routinely post warnings during box jelly windows.
