The Australian dive calendar

Peak summer: warm east-coast water, leopard sharks and mantas in the north, cyclone watch in the tropics.

• • Byron Bay & Tweed
• • North Stradbroke Island
• • Tasmania east coast

The southern states' best month: settled weather from Sydney to Perth, and the start of Victoria's prime season.

• • Port Phillip Heads
• • Rottnest Island
• • Fleurieu Peninsula

Autumn arrives: whale sharks return to Ningaloo, the south is calm and clear, and the east coast water is at its warmest.

• • Ningaloo – Exmouth
• • Wilsons Promontory
• • Esperance

The best all-round month in the south and west: whale sharks peaking, Perth and Victoria calm, Sydney clearing.

• • Ningaloo – Exmouth
• • Perth
• • Mornington Peninsula

Manta season opens at Lady Elliot, the cuttlefish arrive at Whyalla, and the spider crabs pile up under Victoria's piers.

• • Lady Elliot Island
• • Mornington Peninsula
• • Whyalla

Dry season on the reef, dwarf minke whales on the Ribbons, and the start of the grey nurse and humpback winter.

• • Ribbon Reefs
• • Whyalla
• • South West Rocks

Mid-winter: the Great Barrier Reef at its clearest, cuttlefish and minkes in their last weeks, whales everywhere.

• • Cairns
• • Lady Elliot Island
• • Forster & Seal Rocks

Humpback swims at Ningaloo, mantas peak at Lady Elliot, and Port Jackson sharks and cuttlefish breed in the south.

• • Ningaloo – Exmouth
• • Heron Island
• • Wollongong & Kiama

Spring: the Coral Sea and Rowley Shoals seasons open, the reef's winds ease, and the south begins to warm.

• • Coral Sea
• • Rowley Shoals
• • Townsville

Arguably the best month of all: the Yongala, Osprey Reef, the Rowley Shoals, the far northern reef and Ningaloo all in season.

• • Far Northern Reef
• • Rowley Shoals
• • Townsville

Early summer: warm water on every coast, mantas and leopard sharks arriving in the subtropics, and the wet season in the north.

• • Cocos (Keeling) Islands
• • Byron Bay
• • Geographe Bay