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Dive Seasons In Cairns | Month By Month Guide

What is the best time of year to dive the Great Barrier Reef off Cairns? There is no definite answer to this question. Cairns is a tropical port city, offering scuba divers the closest mainland access to the Great Barrier Reef, which means less time travelling and more time diving! Bordered by towering rainforest mountains on one side and the Coral Sea on the other, Cairns has two distinct seasons ‘wet’ (summer and autumn) and ‘dry’ (winter and spring).

Dive Seasons

Dive Seasons

Coral Gardens

Coral Gardens

Great Visabilty

Great Visabilty


The ‘wet’ season is self-explanatory. This is the time of year Cairns receives most of its annual rainfall and has quite high day time temperatures and humidity. For visitors, the ‘wet’ season (December – May) is generally considered the low season (which means there are more likely to be some great diving specials available!).

The ‘dry’ season (June – November) has lower day time temperatures, humidity and generally, much less rainfall: this is the high season, so there are more visitors and less availability on the dive boats (best to book ahead at this time of year!).

Dry Season

Dry Season

Anemone Fish

Anemone Fish

Wet Season

Wet Season


weather averages for cairns

  Max ° C Min Rainfall mm Water Temp
January 31.1 25.2 39.6 29
Febuary 30.4 25.4 45.5 28
March 29.2 24.8 42.7 27
April 27.9 23.8 19.7 26
May 25.8 22.5 9.0 26
June 24 21.5 4.5 24
July 23.5 20.2 2.9 22
August 24.6 20.4 2.7 22
September 27.3 21.6 3.4 23
October 29.7 23.1 4.7 26
November 31.2 24.2 9.5 26
December 31.6 23.1 18.0 27

As to the best time of year to visit and dive, anytime is a good time to dive on the Great Barrier Reef off Cairns! Some of our best diving has been experienced during the ‘wet’ season (thanks to warm waters), while the ‘dry’ season offers visitors more comfortable day time temperatures and conditions, and once in a lifetime opportunities to swim and dive with Dwarf Minke Whales (more on this below). For your information and reference, we have prepared a month by month overview of Cairns diving conditions and what you can expect to see (see below).

Cairns’ Great Barrier Reef water temperature varies throughout the year, from a comfortable 29 degrees in summer (December – February) to 22 degrees in winter (June – August). While wind and visibility fluctuates daily, pending season and prevailing weather conditions, the marine life on the Great Barrier Reef does not, offering memorable diving all year round.

Indeed, it is the Great Barrier Reef’s biodiversity that make it one of the seven wonders of the natural world. Home to more than 1,500 fish species, 411 types of hard coral, one-third of the world’s soft corals, 134 species of sharks and rays, six of the world’s seven species of marine turtles and more than 30 species of marine mammals, it is always teeming with life. In addition to the ‘usual’ suspects (fish of all shapes, colours and sizes, reef sharks, rays, moray eels and turtles) there are some ‘seasonal’ creatures and events that come and go on Cairns Great Barrier Reef, including the annual appearance of Dwarf Minke and Humpback Whales, coral spawning and the turtle breeding season. These are outlined in the below copy, in the ‘what can I expect to see’ text.

January Diving Conditions in Cairns

January is a great month to go diving off Cairns. This is a summer month and the water temperature can be expected to be a balmy 29 degrees Celsius (84 Degrees Fahrenheit). There is no need for wet suits. Lycra suits are provided on all dive boats, providing protection from the sun and jellyfish. Being close to the equator, Cairns does experience monsoonal weather patterns. In January the days are hot and rainfall is common (but you get wet diving anyway). Tropical cyclones can occur in January and dive operators choose their locations to suit the conditions.

Reef Fish

Reef Fish

Salps

Salps

Six Bar Wrasse

Six Bar Wrasse


What can I expect to see in January?

This month jellyfish, salps and siphonophores of every shape and complexity can be found in the water and are a favourite food source for fish and turtles. Some fish will start spawning in January, including damsels, wrasse, surgeons and parrotfish.

February Diving Conditions in Cairns

February is the last month of summer and traditionally a very ‘wet’ month in Cairns, with high rainfall. Cairns’ Outer Great Barrier Reef dive sites are all about 60km offshore, which means high coastal rainfall does not really affect diving conditions, unless there has been a high intensity cyclone, which is an infrequent occurrence. This is a great month to visit the tropical north, with warm waters for diving and the rainforest alive with flowing waterfalls and streams.

Gorgonian Fan

Gorgonian Fan

Sharks at Osprey

Sharks at Osprey

Remote Diving

Remote Diving


What can I expect to see in February?

This is also the time of year that many turtle species are nesting and hatching. The turtle activity attracts sharks and some of Cairns’ liveaboard dive operators offer extended trips to the remote northern reefs and islands, including Raine Island, allowing divers to witness this marine activity in the remote wilderness.


March Diving Conditions in Cairns

March is an exciting month for diving off Cairns, it’s the first month of autumn so the waters are still warm (around 28 degrees Celsius) and there is generally less rainfall around.

Juvenile Sweetlip

Juvenile Sweetlip

Reef Fish

Reef Fish

Baby Nemo

Baby Nemo


What can I expect to see in March?

Many juvenile fish are starting to appear on the Great Barrier Reef: look out for the juvenile Harlequin Sweetlips, which can be seen mimicking the movement of a poisonous flat worm. Also, Black-tipped Reef Sharks give birth this month with females having between 1 to 10 pups in the inshore estuarine nursery grounds, where the young remain for the next few years.

April Diving Conditions in Cairns

In April the water is starting to cool a little (we’re still a long way from needing wet suits) and the ambient daytime temperatures are starting to become a little cooler. The clear, blue waters are teeming with marine life and it’s a great time of year to go diving.

Glassies on Reef

Glassies on Reef

Nudibranch

Nudibranch

At the Outer Reef

At the Outer Reef


What can I expect to see in April?

Look out for the smaller marine life, such as nudibranchs, cowrie shells and pipe fish. Heads up, not all nudibranchs are nudibranchs: juvenile sea cucumbers mimic the poisonous colours of nudibranchs to fool their predators, so look closely to see if they have feet. This month many of the coral bommies will become hidden by glassies (clear coloured juvenile fish) and if you look closely, you can see the juvenile anemone fish playing hide and seek amongst the anemones.

May Diving Conditions in Cairns

May sees the water starting to cool down and some divers (especially those used to tropical diving conditions) may be taking advantage of the wet suits this month. This is a transitional time of year for weather in Cairns and with winter just around the corner, the trade winds start coming up from the south, triggering a change in population of many migratory species.

Swim Through

Swim Through

Lion Fish

Lion Fish

Fan Coral

Fan Coral


What can I expect to see in May?

As you explore swim throughs on some of the Outer Reef sites, look for gorgonian fans, Lion Fish and the 2-metre Queensland Grouper that frequents the reefs from Cairns.


June Diving Conditions in Cairns

The first month of winter! Water temperatures on Cairns’ Great Barrier Reef are usually around 23 degrees Celsius this month and wet suits are provided on all dive boats. This is an exciting month for diving as not only will you see the ‘usual’ wonders of the Great Barrier Reef, but you might also have an encounter with a Dwarf Minke Whale.

Sweetlips

Sweetlips

Minke Whale

Minke Whale

Cod & Divers

Cod & Divers


What can I expect to see in June?

Your first dive in June has the possibility of becoming a snorkel if the vessel is surrounded by the beautiful Dwarf Minke Whales. This is the only place on earth where you can swim and snorkel with these magical creatures. June is the start of Dwarf Minke Whale season that runs through until the end of July.

July Diving Conditions in Cairns

In July the waters of the Great Barrier Reef are a deep, clear blue: the sky is the only thing matching them for colour intensity. The mornings are crisp and cool and the water temperature on the Coral Sea reaches a low of 22 degrees Celsius (71 degrees Fahrenheit). There is very little rainfall this month and visibility is usually excellent. Note: It can be windy at this time of year and if you suffer from motion sickness, then we highly recommend taking some preventative medication on the morning of travel.

Cuttle Fish

Cuttle Fish

True Nemo

True Nemo

Outer Reef Coral

Outer Reef Coral


What can I expect to see in July?

This month Manta Rays can be seen in clearer waters of the Coral Sea.

August Diving Conditions in Cairns

Diving in August can see travel time to and/or from Cairns to the Great Barrier Reef ‘delayed’ by the presence of Humpback Whales. These magnificent mammals will often stop boats as they breach and tail slap the water nearby. It’s the last official month of winter and the water is as cold as it will get off Cairns (22 degrees Celsius – 71 degrees Fahrenheit). Note: It can be windy at this time of year and if you suffer from motion sickness, then we highly recommend taking some preventative medication on the morning of travel.

Humpback Whale

Humpback Whale

The Small Stuff

The Small Stuff

Magical Migaloo

Magical Migaloo


What can I expect to see in August?

August sees Humpback Whales visiting the Outer Reefs from Cairns until late in September, when they slowly return south with their calves. Migaloo, the world’s only all white Humpback Whale is a regular visitor to Cairns’ Great Barrier Reef at this time.


September Diving Conditions in Cairns

September is another great month to go diving from Cairns. The trade winds have started to drop down and often you will have days with total ‘glass out’ conditions. Visibility is usually excellent on Cairns’ Outer Great Barrier Reef dive sites and further north at Osprey Reef in the Coral Sea. Osprey Reef offers 1,000 feet drop offs and hundreds of reef sharks: this can only be visited on a liveaboard dive trip from Cairns.

Green Turtle

Green Turtle

Humpback Breaching

Humpback Breaching

Octopus

Octopus


What can I expect to see in September?

Some Great Barrier Reef fish species, including Snappers and Red Throat Emperors, start to aggregate in the reef’s shallows in preparation for spawning. You will also see many marine turtles feeding on sea grasses and algae.

October Diving Conditions in Cairns

We are well into spring now and the waters are warming back up. The winds have generally dropped off and diving conditions from Cairns on the Great Barrier Reef are looking good.

What can I expect to see in October?

This is the time of year that breeding activity begins for most seabird species, so if you happen to be going to an island or cay (Michaelmas Cay is a great place to visit right now) you may be able to experience the noise and activity associated with breeding season. This is also the time for turtle mating and nesting, so you may see more turtles around than usual.

Colourful Reef Fish

Colourful Reef Fish

Nesting Sea Birds

Nesting Sea Birds

Schooling Fish

Schooling Fish


November Diving Conditions in Cairns

Cairns is heating up this month and so is the Great Barrier Reef, in preparation for its annual coral spawning! In November you can ditch the wet suits and return to the lycra suits, with water temperatures returning to around 27-8 degrees Celsius. The winds are down and the pool is open, another great month for diving on Cairns’ Great Barrier Reef.

Slipper Lobster

Slipper Lobster

Moray Eel

Moray Eel

Wobbegong Shark

Wobbegong Shark


What can I expect to see in November?

If you are lucky enough to be here in Cairns diving in November for coral spawning, you will see the reef come alive with Decorator Crabs, Slipper Lobsters and Palao Worms. NB: coral spawning can occur in either November or December: for more information, please visit our coral spawning page.


December Diving Conditions in Cairns

Summer is here! Cairns offers hot, humid days and nights with the clear, blue waters of the Great Barrier Reef a cool retreat for divers. Underneath the surface, visibility is good and there is lots of life, following the recent coral spawning of the Great Barrier Reef.

Potato Cod & Diver

Potato Cod & Diver

Trigger Fish

Trigger Fish

Star Puffer

Star Puffer


What can I expect to see in December?

Lots of Great Barrier Reef fish breed in December. Keep an eye out for anemone fish (Nemo!), with their bright orange eggs, and Triggerfish. In particular be aware of (and careful of) the larger Titan Triggerfish. Summer is their breeding season and the time of year when these fish become quite aggressive. Divers will be provided with information and advice on this, onboard the dive boats.

Cairns Dive Seasons FAQ

When can I see whales / dolphins on the Great Barrier Reef?

If you are hoping to see whales on Cairns’ Great Barrier Reef then June / July is the Dwarf Minke Whale season and they are commonly sighted on the remote reefs of the Far Northern Ribbon Reefs. This is a popular time of year to visit, as these magnificent mammals are very inquisitive and commonly approach snorkellers and divers in the water. Humpback Whales are shyer and do not normally approach divers or snorkellers in water, however, it is quite common for them to offer displays of breaching, rolling and fin slaps, to passengers travelling to the Outer Reefs on day trips from Cairns, in late August to September. Dolphins can be seen all year round, most often seen playing in the bow water of a moving vessel. Occasionally divers in water may hear them calling with high pitched whistles and clicking, but it is extremely rare for them to approach Cairns divers.

Can I dive when it is raining in Cairns?

Yes, you can dive when it’s raining in Cairns, you are going to get wet anyway! Cairns has a tropical climate with an annual monsoonal ‘wet’ season. The weather is hard to predict and sometimes when it’s raining in Cairns, it’s not raining at the reef and vica versa. Rain itself will not impact on your day and diving.

Cyclones and diving on the reef, what’s the impact?

The Great Barrier Reef has evolved with tropical cyclones over thousands of years. A tropical cyclone is a severe weather system with high winds and rainfall. Its severity varies. Tropical cyclones can impact much of Queensland’s coastline, but are mostly experienced in the north, anywhere from Cape York Peninsula down to Mackay, during the summer months (DecemberFebruary). Their impact on the reef varies, pending their intensity. There may be some coral damage, although the marine life is still present and can be seen by divers. As it is a natural process, the reef does recover from the impact of cyclonic events. Cyclones are closely monitored by dive operators, who adjust their operations to suit conditions. Generally, cyclones will only impact dive operations for a few days each year during summer. Of course the weather is variable and can not be predicted: for more information at the time of your visit, please contact Cairns Dive Adventures.

When is the best time of year to dive in Cairns?

Diving the Great Barrier Reef from Cairns can be brilliant at any time of year. For detailed information, please see our Dive Seasons In Cairns page.

Is it safe to scuba dive with jellyfish?

There are poisonous jellyfish (marine stingers) present in the waters around Cairns and the Great Barrier Reef at various times during the year. By taking appropriate precautions (wearing the lycra suits provided or for hire etc) and following the advice provided on the dive boats, scuba diving should be safe at any time. For more information on this, please see our Cairns Jellyfish Page.

Of course this is a guide only. Diving all year round on Cairns’ Great Barrier Reef you can expect to see turtles, sharks, bright corals, sting rays, pipefish, sea snakes, Queensland grouper, Maori wrasse and much more. For those interested in the smaller, colourful colours of nudibranchs, they can be sighted all year round as well.

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Selected Tours

M.V. Reef Kist – Cairns Dive Centre

Cairns' cheapest dive / snorkel Great Barrier Reef day tour. Includes all equipment and hot / cold buffet lunch. Visit up to 2 reef sites, with up to 4 hours on the Great Barrier Reef.
$130.00
Cairns Dive Centre


Deep Sea Divers Den: Reef Quest

Value for money Great Barrier Reef day tour. Visits 2 reef sites. Perfect for snorkellers, certified divers and those wanting to try an introductory dive. Buffet lunch included.
$160.00
Cairns Great Barrier Reef snorkle tours on Reef Quest


Tusa Dive T6

Tusa Dive provide quality Great Barrier Reef snorkel / dive day tours on Cairns' newest reef day boat, T6. Up to 5 hours on the reef, visiting 2 locations. Great service - all meals included.
$190.00
Tusa at the Reef


Fitzroy Island Ferries

Fitzroy Island Ferries have three (3) convenient departure and return times from Cairns to Fitzroy Island, making this great for half day or full day tours.
$69.00
DSC_0217


Great Adventures: Green Island – Full Day

Great Adventures offer two departure (8.30am - 10.30am) and return times (2.30pm - 4.30pm) for their full day tours. Flexible option, suitable for families.
$84.00
DSC_0136


Ocean Free

Unique Cairns to Green Island sailing day tour. Max number of guests = 35. Snorkelling & diving plus time on Green Island. Buffet lunch + morning and afternoon tea included. Friendly crew.
$140.00
Scuba diving Green Island


Passions Of Paradise

Australian Tourism Award Winner. Daily dive / snorkel trips to Michaelmas Cay & Paradise Reef on 25m sailing catamaran. Free scuba demonstration & guided snorkel tour. Hot / cold buffet lunch.
$159.00
Passions of Paradise at Michaelmas Cay, Great Barrier Reef


Down Under Dive – Osprey V

Well priced Great Barrier Reef day tour, including BBQ lunch. 5 hours on the reef at 2 reef sites. Guided snorkelling tours and introductory (no experience necessary) and certified diving.
$159.00
Osprey 5 Cruising


Seastar Cruises

Seastar provides daily dive and snorkel tours to Michaelmas Cay and Hastings Reef. Up to 5 hours at the reef and 2 guided snorkel tours included.
$165.00
michaelmas-cay


Ocean Freedom

Locally owned & operated. 5 star service. Up to 6 hours snorkel / dive time at 2 Great Barrier Reef locations. Best reef tour lunch in town. Friendly crew, glass bottom boat tour & much more.
$185.00
Ocean Freedom the quickest Great Barrier Reef day tour dive in Cairns


Reef Experience

Cairns' only fully inclusive day tour, including: city transfers, trip to Great Barrier Reef, 6 hours on reef, 2 reef locations, meals, free scuba dive, marine biologist presentation & equipment.
$185.00
Fully inclusive Great Barrier Reef day tours with Reef Experience


Reef Magic – Marine World

Up to 5 hours at the reef. Outer Great Barrier Reef pontoon with fabulous coral gardens. Meet Wally! Lots of inclusions: snorkelling, glass bottom boat, semi-sub, underwater observatory and more.
$190.00
Reef Magic Outer Reef Scuba Diving


Silverswift

Only Cairns Great Barrier Reef day tour to visit 3 different reef sites in one day! Part of the Quicksilver Cruises fleet. Comfortable, high speed catamaran. Up to 5 hours at the reef.
$190.00
Silverswift At The Reef


Sunlover Cruises

Great day tour for people of all ages. Visit Outer Reef Pontoon at Moore Reef, with lots of inclusions: snorkelling, glass bottom boat and semi-sub tours, underwater observatory and more.
$190.00
Sunlover Cruises


Silversonic

Silversonic provides daily reef tours departing from Port Douglas and visiting the ribbon reefs at Agincourt Reef. 5 hours at reef and up to 3 dives.
$208.00
DDGSilversonic009


Great Adventures: Outer Reef

Leaves later than most (10am) and provides up to 3 hours at their outer reef pontoon. Enjoy the sun deck, underwater observatory, semi-submersible and many optional extras.
$214.00
Great Adventures


Quicksilver Outer Great Barrier Reef Cruises

Quicksilver Cruises provides the only Port Douglas Great Barrier Reef pontoon tour, departing Marina Mirage daily. Can snorkel and dive.
$219.00
QS_OBRAerialPlatform_AgincourtReef1


Poseidon Snorkel and Dive

Poseidon provides daily tours from Port Douglas to the Agincourt Ribbon Reefs, visiting three (3) separate reef sites. Suitable for divers and snorkelers.
$220.00
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Great Adventures: Green Island & Great Barrier Reef

This is the only Cairns day tour to combine time on Green Island with a visit to a Great Barrier Reef pontoon. Best of both worlds. Suitable for snorkellers and divers.
$228.00
Great Adventures Green Island & Reef Package


Do you need help choosing?

Can't decide? We have personally been on every Cairns reef and diving trip. We can help you choose the best tour, to suit your experience and budget.

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