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Grand Cayman Bio Bay in April 2027: darkest nights

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

16 pitch-dark nights, 18 dark nights

New moon Tue 6 Apr · Full moon Tue 20 Apr

Night by night, April 2027

NightMoon19:0020:30Best
Thu 1 Apr 22%●●●●●●●●●●20:30
Fri 2 Apr 15%●●●●●●●●●●20:30
Sat 3 Apr 9%●●●●●●●●●●20:30
Sun 4 Apr 4%●●●●●●●●●●20:30
Mon 5 Apr 1%●●●●●●●●●●20:30
Tue 6 Apr 0%●●●●●●●●●●20:30
Wed 7 Apr 2%●●●●●●●●●●20:30
Thu 8 Apr 6%●●●●●●●●●●20:30
Fri 9 Apr 12%●●●●●●●●●●20:30
Sat 10 Apr 20%●●●●●●●●●●20:30
Sun 11 Apr 30%●●●●●●●●●●20:30
Mon 12 Apr 41%●●●●●●●●●●20:30
Tue 13 Apr 53%●●●●●●●●●●20:30
Wed 14 Apr 65%●●●●●●●●●●20:30
Thu 15 Apr 76%●●●●●●●●●●20:30
Fri 16 Apr 85%●●●●●●●●●●20:30
Sat 17 Apr 92%●●●●●●●●●●20:30
Sun 18 Apr 97%●●●●●●●●●●20:30
Mon 19 Apr 99%●●●●●●●●●●19:00
Tue 20 Apr 100%●●●●●●●●●●19:00
Wed 21 Apr 98%●●●●●●●●●●19:00
Thu 22 Apr 94%●●●●●●●●●●20:30
Fri 23 Apr 88%●●●●●●●●●●20:30
Sat 24 Apr 82%●●●●●●●●●●20:30
Sun 25 Apr 74%●●●●●●●●●●20:30
Mon 26 Apr 65%●●●●●●●●●●20:30
Tue 27 Apr 56%●●●●●●●●●●20:30
Wed 28 Apr 47%●●●●●●●●●●20:30
Thu 29 Apr 37%●●●●●●●●●●20:30
Fri 30 Apr 28%●●●●●●●●●●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 April 2027?

The darkest nights are Thu 1 Apr, Fri 2 Apr, Sat 3 Apr, Sun 4 Apr, Mon 5 Apr, Tue 6 Apr, Wed 7 Apr, Thu 8 Apr, Fri 9 Apr, Sat 24 Apr and more. 18 of 30 nights score at least 4 out of 5.

Which nights should I avoid in April 2027?

Avoid the nights around the full moon on Tue 20 Apr, when moonlight washes out the glow.

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

19:00 is the darker choice on 0 nights; 20:30 is the darker choice on 19 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).