Manialtepec Lagoon: 19:30 or 21:00 tour?
Swimming in the glowing water is allowed from the boats. Bioluminescence is only visible in real darkness, so the moon and the end of twilight decide which tour is worth it. Pick your date.
Short answer: On 2 Nov 2026, the 19:30 tour at Manialtepec Lagoon is the darker choice (darkness 5/5, moon down, sky dark). The darkest nights in the next 30 days are Mon 2 Nov, Tue 3 Nov, Wed 4 Nov, Thu 5 Nov, Fri 6 Nov.
Mon 2 November 2026
Book the 19:30 tour
Darkness 5/5 ●●●●● · moon down, sky dark
| 19:30 tour | ●●●●● Pitch dark | moon down, sky dark |
|---|---|---|
| 21:00 tour | ●●●●● Pitch dark | moon down, sky dark |
Sunset 17:58 · Fully dark 19:12 · Moonrise 00:30, moonset 13:37 · Moon 35% lit (last quarter)
Next 30 nights
| Night | Moon | 19:30 | 21:00 | Best |
|---|---|---|---|---|
| Mon 2 Nov | 35% | ●●●●● | ●●●●● | 19:30 |
| Tue 3 Nov | 25% | ●●●●● | ●●●●● | 19:30 |
| Wed 4 Nov | 16% | ●●●●● | ●●●●● | 19:30 |
| Thu 5 Nov | 9% | ●●●●● | ●●●●● | 19:30 |
| Fri 6 Nov | 4% | ●●●●● | ●●●●● | 19:30 |
| Sat 7 Nov | 1% | ●●●●● | ●●●●● | 19:30 |
| Sun 8 Nov | 0% | ●●●●● | ●●●●● | 19:30 |
| Mon 9 Nov | 1% | ●●●●● | ●●●●● | 19:30 |
| Tue 10 Nov | 4% | ●●●●● | ●●●●● | 19:30 |
| Wed 11 Nov | 9% | ●●●●● | ●●●●● | 21:00 |
| Thu 12 Nov | 15% | ●●●●● | ●●●●● | 21:00 |
| Fri 13 Nov | 22% | ●●●●● | ●●●●● | 21:00 |
| Sat 14 Nov | 30% | ●●●●● | ●●●●● | 21:00 |
| Sun 15 Nov | 39% | ●●●●● | ●●●●● | 21:00 |
| Mon 16 Nov | 49% | ●●●●● | ●●●●● | 21:00 |
| Tue 17 Nov | 59% | ●●●●● | ●●●●● | 19:30 |
| Wed 18 Nov | 68% | ●●●●● | ●●●●● | 19:30 |
| Thu 19 Nov | 78% | ●●●●● | ●●●●● | 19:30 |
| Fri 20 Nov | 86% | ●●●●● | ●●●●● | 19:30 |
| Sat 21 Nov | 92% | ●●●●● | ●●●●● | 19:30 |
| Sun 22 Nov | 97% | ●●●●● | ●●●●● | 19:30 |
| Mon 23 Nov | 100% | ●●●●● | ●●●●● | 19:30 |
| Tue 24 Nov | 99% | ●●●●● | ●●●●● | 19:30 |
| Wed 25 Nov | 96% | ●●●●● | ●●●●● | 19:30 |
| Thu 26 Nov | 91% | ●●●●● | ●●●●● | 19:30 |
| Fri 27 Nov | 83% | ●●●●● | ●●●●● | 19:30 |
| Sat 28 Nov | 73% | ●●●●● | ●●●●● | 19:30 |
| Sun 29 Nov | 63% | ●●●●● | ●●●●● | 19:30 |
| Mon 30 Nov | 51% | ●●●●● | ●●●●● | 19:30 |
| Tue 1 Dec | 40% | ●●●●● | ●●●●● | 19:30 |
Season
Best August to December.
Manialtepec Lagoon darkest nights by month
How the darkness score works
For each tour slot we follow the sky for 90 minutes. Twilight scores against you until the sun is 18° below the horizon. The moon counts in proportion to how much of it is lit and how high it is. 5 means pitch dark; 1 means the glow will be hard to see. Clouds, rain and the health of the plankton also matter and are not in the score.
Times are local (America/Mexico_City). Calculated, not observed; tour operators set the real departure times.
Questions
19:30 or 21:00: which Manialtepec Lagoon tour is better?
It depends on the moon and twilight on your night. Over the next 30 nights, the 19:30 tour is darker on 15 nights and the 21:00 tour is darker on 5 nights. Tonight the 19:30 tour scores 5/5.
When is the best time to see the bioluminescence at Manialtepec Lagoon?
Best August to December. Within any month, go around the new moon, on a night when the moon is below the horizon during your tour. The next new moon is on 9 Nov 2026.
Does a full moon ruin the bioluminescence at Manialtepec Lagoon?
Yes. A bright moon above the horizon washes out the glow, and some operators cancel tours. The next full moon is on 24 Nov 2026; avoid the nights around it.