Bio Bay in the Rain: can you still see the glow?
Yes, you can still see the bio bay glow in the rain. The plankton flash whenever the water moves, and a Vieques guide once told NPR that rain lights up the whole surface. All three tours cancel free up to 24 hours before, and if we call one off for unsafe weather, you get a full refund. Book a dark night early in your trip and keep a second night free.
Can you see the bio bay in the rain?
Yes. The glow comes from Pyrodinium bahamense, a microscopic plankton that flashes blue-green when the water around it is disturbed, as Scientific American explains. Paddles, hands and raindrops all disturb the water. After Hurricane Maria, a Vieques guide told NPR that when it rains, the whole surface of the water is alight.
So a shower can add sparkle to the night. Dress for it the way you would for any bio bay tour: clothes that can get wet, a dry change for later and a small dry bag for your phone. Our guide to what to wear to the bio bay has the full list for each tour.
Do bio bay tours run in the rain?
Each tour has its own weather plan, and safety decides. Our Vieques tour runs in light rain, and if the weather turns dangerous it is called off and you choose a new date or a full refund. On the Fajardo and La Parguera tours, if we cancel because the weather is unsafe, you get a full refund. All three tours have free cancellation up to 24 hours before.
- Free cancellation up to 24 hours before any of our three tours.
- A full refund if we cancel the Fajardo or La Parguera tour for unsafe weather.
- A new date or a full refund, your choice, if the Vieques tour is called off.
Watching the forecast before your tour? Call or text (787) 209-2127 and we will help you choose between your nights.
Clouds, wind and the moon
Clouds and wind change from one evening to the next, and nobody can forecast them weeks ahead. The moon is different: its phase, rise and set are known years in advance, and moonlight on the water is what makes the glow harder to see. Plan your bio bay night around the moon, then let the weather be a bonus.
A cloudy evening can even hide a bright moon. And on brighter nights at Laguna Grande, our guides bring a large tarp to block the light so the group still sees the glow. For the best months and seasons, see the best time to see the bio bay.
Tonight's skySee the darkest nights on the moon calendarIs the bio bay still glowing after storms?
Yes. Puerto Rico's three bio bays glow year-round, as Discover Puerto Rico notes. A big storm can dim a bay for a while, and the bays have come back each time. After Hurricane Maria in 2017, Mosquito Bay and Laguna Grande went dark for a spell and recovered, while La Parguera was largely spared, says the Latz Lab at Scripps.
Smaller dips have come and gone too: Laguna Grande dimmed in 2003 and again in late 2013 and rebounded (Christian Science Monitor). A 2024 study of Laguna Grande even describes hurricanes raking and refreshing the lagoon.
How bright any one night looks depends on moonlight, weather and water conditions, so nobody can promise a level of brightness. A dark sky gives you the best view, and that part you can plan.
Plan a backup night for the bio bay
Book your bio bay night early in your stay and keep a second dark night free. If the weather turns, you still have a night to move to. The moon calendar shows the darkest nights of your trip, and our Fajardo tour runs every night of the year, so a backup night is easy to find.
Pick two dark nights
Open the bio bay moon calendar, enter your dates and note the two darkest nights, ideally early in your trip.
Book the first one
Contact us on WhatsApp with the night you want. Free cancellation up to 24 hours before keeps you flexible.
Keep the second night open
If the weather moves in, call or text (787) 209-2127 and we will help you change your plans.
Planning La Parguera? That tour runs on select nights each month, so check its dates on the calendar first. Still choosing a bay? See which bio bay fits your trip.
Is the bio bay safe?
Yes, a guided tour is a relaxed way to see it. On our Fajardo tour you get a kayak lesson and safety briefing on shore, a life jacket and a guide who is on the water with you the entire time. On Vieques, a local guide leads the paddle in two-person clear kayaks. On all three tours, safety comes first, and a tour is called off when the weather is unsafe.
No kayaking experience is needed for the Fajardo tour, and kids from age 6 can come along with an adult in their kayak. Wondering what the night is really like? Read is the bio bay worth it.
Bio bay rain and weather questions
Can you see bioluminescence in the rain?
Yes. The plankton that light up Puerto Rico's bio bays flash whenever the water around them moves, and raindrops move it. A Vieques guide told NPR that when it rains, the whole surface of the water is alight. Wear clothes that can get wet, keep your phone in a small dry bag and enjoy the show.
Do bio bay tours run in the rain?
Our Vieques tour runs in light rain. On the Fajardo and La Parguera tours, if we cancel because the weather is unsafe, you get a full refund, and if the Vieques tour is called off you choose a refund or a new date. Safety comes first, and all three tours have free cancellation up to 24 hours before.
What happens if my bio bay tour is cancelled for weather?
You get a full refund if we cancel the Fajardo or La Parguera tour because the weather is unsafe. If the Vieques tour is called off, you choose a full refund or a new date. Either way, call or text (787) 209-2127 and we will help you find another dark night during your trip.
Does rain make the bio bay brighter or dimmer?
Raindrops set off flashes of their own, since they disturb the water, and guides have described the whole surface lighting up in a shower. How bright a night looks overall depends on moonlight, weather and water conditions, so nobody can promise a level. A dark, moonless sky is the part you can plan for.
Is the bio bay still glowing?
Yes. Puerto Rico's three bioluminescent bays, Laguna Grande in Fajardo, Mosquito Bay on Vieques and La Parguera in Lajas, glow year-round. Brightness changes from night to night with moonlight, weather and water conditions, which is why we suggest picking the darkest night of your trip on the moon calendar.
Did Hurricane Maria affect the bio bays?
Yes, for a while: after Hurricane Maria in 2017, Mosquito Bay and Laguna Grande went dark for a spell and then recovered, and La Parguera was largely spared, according to a Scripps Institution of Oceanography scientist. The bays have come back after storms before, which shows how resilient they are.
Is cloudy weather good for the bio bay?
It can be, because clouds can hide a bright moon and a darker sky makes the blue-green glow easier to see. Clouds are hard to forecast more than a few days out, though, so plan around the moon first with the moon calendar and treat a cloudy evening as a possible bonus.
Does the moon matter more than the weather?
The moon is the part you can plan. Moonlight on the water makes the glow harder to see, and our moon calendar rates every night of your trip by how much moonlight reaches the water during tour hours. Weather changes from day to day, so pick a dark night first and keep a backup.
What should I do if rain is forecast for my bio bay night?
Keep your plans and check in with us. If we call off a tour for unsafe weather, you get a full refund, and on Vieques you can choose a new date instead. To move nights, all three tours cancel free up to 24 hours before, and we will help you pick another dark night on the moon calendar.
Is Mosquito Bay safe?
Yes, our Vieques tour is a calm, guided night. A local guide leads the paddle in two-person clear kayaks, ages 3 and up can join, and the van from Esperanza to the bay and back is included. If the weather turns dangerous, the tour is called off and you choose a new date or a full refund.
Are there sharks in the bioluminescent bay?
We cannot give you a species list, but on all three of our tours you stay in a kayak or on a boat with a guide leading the group, so sea life is something you watch from above. On our Fajardo tour the guide is on the water with you the entire time, so ask about anything you spot.
Are there jellyfish in the bio bay?
We cannot promise what drifts by on a given night, but on all three of our tours you watch the glow from a kayak or a boat, not from the water. At Laguna Grande you can trail a hand through the glowing water from your kayak while your guide explains what makes it light up.
Are there mosquitoes at the bio bay?
Sometimes, because the bays are lined with mangroves and mangroves at night can bring biting insects, so bring repellent. Bug spray is on the packing list for the Fajardo tour. The Vieques tour asks for DEET-free repellent, if any, because Mosquito Bay is a protected reserve. Light clothes that can get wet work well.
Pick your night, then enjoy the glow
Send us your travel dates on WhatsApp. We will suggest the darkest nights and help you keep a backup night free.