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Grand Cayman Bio Bay in November 2026: darkest nights

Boat tours leave from Rum Point and Kaibo. Operators cancel on bright full-moon nights. Year-round.

17 pitch-dark nights, 18 dark nights

New moon Mon 9 Nov · Full moon Tue 24 Nov

Night by night, November 2026

NightMoon19:0020:30Best
Sun 1 Nov 47%●●●●●●●●●●20:30
Mon 2 Nov 36%●●●●●●●●●●20:30
Tue 3 Nov 25%●●●●●●●●●●20:30
Wed 4 Nov 16%●●●●●●●●●●20:30
Thu 5 Nov 9%●●●●●●●●●●20:30
Fri 6 Nov 4%●●●●●●●●●●20:30
Sat 7 Nov 1%●●●●●●●●●●20:30
Sun 8 Nov 0%●●●●●●●●●●20:30
Mon 9 Nov 1%●●●●●●●●●●20:30
Tue 10 Nov 4%●●●●●●●●●●20:30
Wed 11 Nov 8%●●●●●●●●●●20:30
Thu 12 Nov 14%●●●●●●●●●●20:30
Fri 13 Nov 21%●●●●●●●●●●20:30
Sat 14 Nov 29%●●●●●●●●●●20:30
Sun 15 Nov 38%●●●●●●●●●●20:30
Mon 16 Nov 48%●●●●●●●●●●20:30
Tue 17 Nov 58%●●●●●●●●●●20:30
Wed 18 Nov 68%●●●●●●●●●●20:30
Thu 19 Nov 77%●●●●●●●●●●20:30
Fri 20 Nov 85%●●●●●●●●●●20:30
Sat 21 Nov 92%●●●●●●●●●●20:30
Sun 22 Nov 97%●●●●●●●●●●20:30
Mon 23 Nov 99%●●●●●●●●●●19:00
Tue 24 Nov 99%●●●●●●●●●●19:00
Wed 25 Nov 97%●●●●●●●●●●19:00
Thu 26 Nov 91%●●●●●●●●●●19:00
Fri 27 Nov 84%●●●●●●●●●●19:00
Sat 28 Nov 74%●●●●●●●●●●20:30
Sun 29 Nov 63%●●●●●●●●●●20:30
Mon 30 Nov 52%●●●●●●●●●●20:30

Check one night in detail Grand Cayman Bio Bay tours

Questions

What are the best nights to see the bioluminescence at Grand Cayman Bio Bay in November 2026?

The darkest nights are Sun 1 Nov, Mon 2 Nov, Tue 3 Nov, Wed 4 Nov, Thu 5 Nov, Fri 6 Nov, Sat 7 Nov, Sun 8 Nov, Mon 9 Nov, Tue 10 Nov and more. 18 of 30 nights score at least 4 out of 5.

Which nights should I avoid in November 2026?

Avoid the nights around the full moon on Tue 24 Nov, when moonlight washes out the glow.

19:00 or 20:30: which Grand Cayman Bio Bay tour is darker in November?

19:00 is the darker choice on 2 nights; 20:30 is the darker choice on 18 nights.

Grand Cayman Bio Bay darkness by month

Darkness score 1-5 per tour slot from twilight and moonlight. Weather and plankton health are not included. Times are local (America/Cayman).