Isla Mujeres lies just 13 km from Cancún, so temperatures and the rainy season are practically the same in both places.

However, when planning a stay on the island itself, two much more important factors come into play: the wind and the specific beach’s location.

Whilst the sea on the west coast and at Playa Norte can be calm and almost free of seaweed, the east coast is affected by waves and sargassum on the very same day. Furthermore, for boat trips, wind strength is more important than the rain itself.

If you’re looking for the most stable weather possible, we’d recommend February or March.

Good conditions usually prevail from late November to April. Conversely, we wouldn’t choose September or October for a short holiday focused mainly on the beaches.

We describe the detailed temperature and rainfall patterns for the entire north coast in the section on Weather in Cancún. Here, we’ll focus on what’s important specifically for Isla Mujeres.

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Which side of the island has the best weather for swimming?

Isla Mujeres is only about 8 km long. You therefore need not worry about differences in temperature or rainfall between different parts of the island.

What matters is which direction the beach faces.

Playa Norte and Playa Centro

The northern and north-western ends of the island offer the best conditions for traditional swimming.

Playa Norte has shallow water, mostly just small waves, and has long been one of the spots with the lowest likelihood of sargassum in the entire Mexican Caribbean.

However, even here, clear and calm seas are not guaranteed every day. When there is a strong northerly wind, the water can become murky and the waves can grow stronger.

The western and south-western coasts

Beaches facing towards Cancún tend to be sheltered from the usual easterly currents and often have calmer waters and less sargassum.

However, most of the coastline is taken up by smaller hotel beaches and resorts.

We stayed at Impression Isla Mujeres on the west coast. The hotel beach is small, but during our stay it was clean and free of sargassum. A bonus was the stunning sunsets over Cancún.

The east coast

The eastern side faces out onto the Caribbean Sea. Larger waves, stronger winds and seaweed are more common here.

This stretch of coast is best suited for scenic views and stop-offs during a tour of the island, rather than for a full day’s swimming. The same applies to the rocky southern coast around Punta Sur.

If the beach is your top priority, when choosing a hotel, look at the map first and the photos second.

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When is the rainy season on Isla Mujeres?

The rainier part of the year lasts from May to October. The highest risk of heavy and prolonged rainfall occurs in September and October.

A rain icon in the daily forecast doesn’t necessarily mean a rainy holiday.

A typical tropical shower can be intense, but it’s over within an hour and the sun is shining again. However, when a tropical wave or storm passes through, overcast weather and rain can last for several days.

On Isla Mujeres, bad weather is a bigger problem than when staying in Cancún or on the Riviera Maya. The island offers very few indoor activities, and most of the main activities take place on the beach or on a boat.

On a day trip from Cancún, we would therefore advise the following:

• Don’t let the usual afternoon showers put you off – set off as early as possible in the morning
• If it rains all day, postpone your visit until another day
• If there are strong winds, check the ferry and boat trip services directly with the operator
• Treat the ten-day forecast as a rough guide only and base your decisions on the outlook for the next 24 to 48 hours

If you’re spending several days in Cancún, don’t leave Isla Mujeres until the very end of your stay. This will give you a buffer in case the boats can’t sail due to the weather.

Sargassum on Isla Mujeres

Sargassum most commonly appears in the Mexican Caribbean from April to October, with the largest quantities usually arriving between May and August.

However, Isla Mujeres cannot be viewed as a single beach.

Whilst the open eastern coast may be full of seaweed, Playa Norte and the western side of the island can remain almost clear on the same day.

That is precisely why Isla Mujeres is the best choice for an off-season seaside holiday – it is practically free of seaweed.

However, even here you cannot be 100 per cent certain. The amount of seaweed can change depending on the wind and sea currents, even within a single day.

We explore this topic in detail, including our own map, in the article ‘Sargassum in Mexico: where to find clean beaches’.

Do ferries to Isla Mujeres run in rain and wind?

When travelling to Isla Mujeres, keep an eye on the wind as well as the rain. A brief shower usually won’t affect ferry services, but strong winds and high waves will.

Large passenger ferries between Puerto Juárez and Isla Mujeres can cope with rougher conditions than small excursion boats.

It may therefore happen that a regular ferry continues to operate, but snorkelling at MUSA, a trip to Isla Contoy or swimming with whale sharks is cancelled.

Nor do port restrictions necessarily apply equally to all vessels. You should therefore always check the current situation with the specific operator or tour organiser.

You can also find public ferry timetables in the section ‘How to get to Isla Mujeres’.

When to swim with whale sharks?

The official season for observing and swimming with whale sharks runs from 15 May to 17 September. If we were to choose a time of year primarily for this activity, we would head to Isla Mujeres between June and August.

Unfortunately, this period coincides with higher humidity, more frequent showers and sargassum. Furthermore, the trips themselves head far out to the open sea and are much more susceptible to the wind than a regular ferry from Cancún.

You should therefore not plan the trip for the last day of your stay and should choose an option with reasonable terms for changes or cancellations. Even in good weather, an encounter with the animals cannot be 100 per cent guaranteed.

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Hurricane season

The Atlantic hurricane season officially runs from 1 June to 30 November.

The highest level of activity is typically concentrated between August and October, with the statistical peak occurring in the first half of September.

This does not mean that there is a risk of a direct hit by a hurricane throughout this entire period. For visitors to Isla Mujeres, the more common complications are several days of rain, strong winds, cancelled trips and restrictions on boat transport.

September and October are the only months when we would generally advise against planning a short holiday focused on beaches and boat trips.

How warm is the sea?

The Caribbean Sea off Isla Mujeres is suitable for swimming all year round.

It is usually at its coolest in February, when the temperature is around 26 °C. From May onwards, it warms up rapidly, reaching around 29 to 30 °C between August and October.

Far more important than a difference of a few degrees is the wind and sea conditions. In winter, strong winds can be unpleasant after getting out of the water, whilst in summer the sea offers little relief from the heat. Furthermore, the very shallow water at Playa Norte heats up even faster in the sun.

Weather on Isla Mujeres by month

Month	Our rating	What to expect on Isla Mujeres
January	Very good	Dry and pleasant temperatures, but also high prices
February	Best	Little rain, lower humidity and a low likelihood of sargassum
March	Best	Stable weather, warm sea and excellent beach conditions
April	Very good	Hotter weather, crowds around Easter and the gradual onset of sargassum
May	A good compromise	Increasing humidity and showers; the whale shark season begins
June	Depends on the itinerary	Heat, rain and sargassum, but a good time for whale sharks
July	Depends on the programme	Very warm sea, high humidity and more frequent showers
August	Less certain	Extreme heat and an increasing risk of tropical storms
September	lowest	Peak of the hurricane season and a high risk of several days’ rain
October	low	Rainy and still a high risk of tropical storms
November	Good	The weather gradually improves; the second half of the month is usually the best
December	Very good	Drier weather, lower humidity and very high prices over Christmas

Where can you check the weather forecast?

For a general idea, the forecast on your phone will suffice. Before a boat trip, however, don’t just look at the chance of rain.

• On Windy.com, check wind strength, gusts, wind direction and wave height
• During hurricane season, check the National Hurricane Centre map
• Check current ferry services directly with the ferry company or tour operator
• Check the sargassum situation using recent photos, webcams and the latest reviews of the specific hotel

A forecast more than a week in advance tells you almost nothing in the tropics. For a day trip, it makes sense to base your decision on wind conditions and radar images a day or two beforehand.