Every snorkeling trip off Isla Mujeres is on open water, so the weather decides how your day goes. It is warm all year. The difference between months is rain, storms and wind, and whether the whale sharks are here. Match the month to the Isla Mujeres Snorkeling guided tours you book.
Wind and waves matter more than rain. A calm sea gives clear water, and you see the statues of the museum from the surface. A rough sea stirs up the sand, and the same statues turn into faint shapes. On a windy day the captain may swap a stop or cancel the trip.
Rain rarely stops a reef trip on its own; you are wet anyway. A tropical storm is different: the port closes. The hurricane season runs from 1 June to 30 November, by the US National Hurricane Center's count.
The figures below are SMN-CONAGUA's normals for Cancún, station 23155, across the channel from the island. They are long-run averages from 1991 to 2020, not your forecast.
Highs average 28.7 °C and lows 20.0 °C in Cancún. Expect 103.8 mm of rain on about 11 days. The coolest month. North winds often keep the port closed for Isla Contoy, so keep a spare day. Reef trips run on the calmer days.
Highs average 30.1 °C and lows 20.6 °C in Cancún. Expect 59.3 mm of rain on about 7 days. One of the drier months, with the fewest rain days after March and April. The reef trips and the Contoy day both run.
Highs average 31.5 °C and lows 21.4 °C in Cancún. Expect 38.7 mm of rain on about 5 days. The least rain of the year. Calm, clear mornings give you the best look at the statues of the museum.
Highs average 33.1 °C and lows 22.9 °C in Cancún. Expect 42.3 mm of rain on about 4 days. The fewest rain days of the year, and the heat builds. Book the reef trip a few days ahead, as spring is busy.
Highs average 34.2 °C and lows 24.2 °C in Cancún. Expect 87.0 mm of rain on about 8 days. The whale shark season opens on the 15th. Book the whale shark day early, and pack a long-sleeved shirt for it.
Highs average 34.0 °C and lows 24.9 °C in Cancún. Expect 184.4 mm of rain on about 12 days. Hurricane season opens on the 1st, and rain jumps. Whale shark swims run all month; book a refundable day.
Highs average 34.8 °C and lows 25.0 °C in Cancún. Expect 67.0 mm of rain on about 9 days. The driest of the whale shark months, halfway through the season. Book a day that refunds you in full up to 24 hours ahead.
Highs average 35.1 °C and lows 25.0 °C in Cancún. Expect 102.2 mm of rain on about 12 days. The hottest month. Whale shark swims continue, and so does the storm season, so watch the forecast before you go.
Highs average 34.2 °C and lows 24.6 °C in Cancún. Expect 181.5 mm of rain on about 15 days. The whale shark season closes on the 17th. Rain rises towards autumn, with rain on about 15 days; watch the storm forecast.
Highs average 32.2 °C and lows 23.7 °C in Cancún. Expect 277.1 mm of rain on about 18 days. The wettest month. No whale sharks now; the reefs and the museum run between the showers.
Highs average 30.3 °C and lows 22.3 °C in Cancún. Expect 131.4 mm of rain on about 13 days. Rain eases through the month. Hurricane season ends on the 30th, and reef trips run most days.
Highs average 29.4 °C and lows 21.0 °C in Cancún. Expect 96.6 mm of rain on about 12 days. Drier weather returns and the storm season is over. Reef trips run every day, and Contoy is open.
| Season | Average high | Average low | Rain | Rain days |
|---|---|---|---|---|
| Dry: December–April | 30.6 °C | 21.2 °C | 341 mm | 39 |
| Wet: May–November | 33.5 °C | 24.2 °C | 1031 mm | 86 |
| Whale sharks: mid-May–mid-September | 34.5 °C | 24.7 °C | 622 mm | 56 |
The dry season runs from December to April. March has the least rain, 38.7 mm, and April the fewest rain days. Highs sit around 29 to 33 °C. For the reefs and the museum, it is the easy choice.
The wet season runs from May to November, and it holds the whale sharks and the storms. The swims run from 15 May to 17 September, set by SEMARNAT. October is the wettest month, with 277.1 mm, and it falls after the sharks have gone. For the calendar by goal, see the best time to visit.
Book a morning if you can. A morning trip leaves you the afternoon spare if the sea turns and the trip moves. The whale shark days leave early and take six hours or more, so they fill your day either way.
Midday sun is strong in every month. Wear a long-sleeved shirt on the boat. Put on a reef-safe sunscreen before you board on a reef trip, and none at all on a whale shark day, where SEMARNAT bans it.
Temperatures, rain and rain days are SMN-CONAGUA's climate normals for Cancún, station 23155, 1991–2020, checked 21 September 2026. The hurricane season is the US National Hurricane Center's. The whale shark season and its sunscreen rule are SEMARNAT's, and the January closure at Isla Contoy is CONANP's.
The same three-hour reef and museum run as the shop's standard trip, on a boat that takes eight at most. Reserve admission, snacks, water and drinks are in the fare; bring US$5 cash for the dock fee.
From $88 per person
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Four hours on the reefs and the underwater museum from a downtown office, with lunch in the fare. Drinks are extra, and there is a US$10 dock fee each; infant seats and strollers are welcome.
From $65 per person
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Your own boat and guide for a six-hour whale shark day in season, with lunch, snacks and soft drinks. Pickup from Cancún or a downtown dock; the listing prices it per person, plus US$10 cash each.
From $699 per person
Check AvailabilityNext: pick your season on the best time to visit, see the top snorkeling spots, or compare every trip on Isla Mujeres Snorkeling Tours.