Cairns sits at latitude 16 degrees south. That's as tropical as it gets in Australia. This means two things: it's warm year-round, and the difference between a good trip and a soggy, stung, sunburned disaster comes down to when you book.
I've visited Cairns in every month except February. Here's what each season actually looks like.
This is the money season. Clear blue skies, 19-26°C (comfortable, not scorching), low humidity, and almost zero rain. The water is calm. The reef visibility peaks at 20-30 meters. The sun is intense but not oppressive.
June mornings can be cool — 17°C at sunrise feels fresh after expecting tropical heat. By August, it's warming up but still pleasant. October is the last reliable dry month before the wet creeps in.
Reef conditions are optimal. The calmest seas mean less seasickness on the boat ride out, better underwater visibility, and healthier-looking coral (summer bleaching events haven't occurred yet).
No stingers. June through October is stinger-free in coastal waters. You can swim at beaches without a full-body lycra suit. The Cairns Esplanade Lagoon is pleasant but there's something different about actual ocean swimming without worrying about box jellyfish.
Whale season. Dwarf minke whales visit the outer reef June-July. Humpback whales migrate past August-October. Some reef operators offer swim-with-whales experiences during these months — extraordinary and expensive (AUD $400+).
This is peak tourist season. Reef trips sell out, especially the better operators on weekends. Book outer reef trips 3-5 days ahead. Hotels are at highest prices — expect AUD $150-250/night for mid-range.
The Atherton Tablelands (1 hour west) have waterfalls that are less impressive in the dry season — the cascades thin out significantly. If you want thundering waterfalls, come in the wet.
High. Both international tourists and Australian school holiday periods (June-July, September-October) fill the town. The Cairns Esplanade is busy. Kuranda Scenic Railway books out on weekends.
These transition months are the sweet spot if you're flexible.
November: Humidity rises (30-31°C), occasional afternoon storms roll in, but mornings are clear. Stinger season officially begins — suits are provided on reef trips. The outer reef remains stinger-free.
May: The last of the wet season rain clears, humidity drops, and the waterfalls are still pumping from months of rain. The landscape is green and lush. Stingers are departing. Tourist numbers are low.
Prices drop 20-30% from dry season peaks. AUD $100-150/night for mid-range hotels. Reef trips run discounts — some operators drop prices by AUD $20-30 on weekday departures. Fewer people on platforms and boats.
May specifically is my favorite month for Cairns. The Daintree Rainforest is at its most spectacular after months of rain — every creek is flowing, every fern is unfurled, and the croc-spotting river cruises see more active animals.
November can bring early cyclone warnings — rare but possible. Check Bureau of Meteorology forecasts. May occasionally has lingering wet-season showers, but they're brief.
Hot (28-32°C), humid (70%+), and wet. Not drizzly-wet — dramatically, theatrically wet. Afternoon thunderstorms drop 50mm of rain in an hour, lightning cracks across the sky, and then it clears and the sun comes back. The rain is usually 2-3 hours in the afternoon. Mornings are often clear.
January and February are the wettest months. March sees occasional cyclones (1-2 per season on average — cyclone season officially runs November-April).
The common mistake is writing off the wet season entirely. It has genuine advantages:
Waterfalls are spectacular. The Atherton Tablelands waterfalls — Millaa Millaa, Josephine Falls, Barron Falls — are at full force. They're thin trickles in September; they're roaring curtains of water in February.
Prices crash. Hotels drop to AUD $60-100/night. Reef trips offer 2-for-1 deals. Some operators discount 30-40%. A luxury Daintree lodge that costs AUD $400/night in July might be AUD $200 in February.
Fewer tourists. Dramatically fewer. The Esplanade Lagoon has space. The Daintree feels private. You might be one of 30 people on a reef platform instead of 150.
Reef trips still run. The outer reef is operational 330+ days a year. Weather cancellations happen (maybe 10-15 days per wet season) but most trips go ahead. The water is warmer for snorkeling.
Stingers. Box jellyfish and Irukandji are present in coastal waters. Full-body stinger suits are provided by all operators. Wear them. Stings can be life-threatening. The outer reef (beyond the continental shelf) is generally stinger-free year-round.
Humidity. Walking around Cairns in February feels like walking through warm soup. You'll sweat through your shirt within 10 minutes. AC is essential. Outdoor activities are best before 10 AM or after 3 PM.
Cyclone risk. Low probability in any given week, but it exists. Travel insurance covering cyclone disruptions is essential December-April. If a cyclone warning is issued, follow local advice — Cairns has excellent emergency systems.
Dry season: Light layers (mornings are cool), swimwear, reef-safe sunscreen SPF 50+, hat, sunglasses. A light jacket for June-July evenings.
Wet season: Quick-dry clothing, waterproof jacket (you'll use it daily), insect repellent (mosquitoes are aggressive), reef-safe sunscreen, and acceptance that you'll be damp.
Both seasons: A waterproof phone case (AUD $15 from any Cairns shop), closed shoes for rainforest walks, and your own snorkel mask if you have one.
If you're exploring the region, consider adding the Great Barrier Reef to your itinerary.
For a cooler Australian adventure, Tasmania offers a dramatic contrast with its temperate rainforests and world-class food.
If you're exploring the region, consider adding Sydney to your itinerary.
If you're exploring the region, consider adding Melbourne to your itinerary.
Best month overall: August. Peak dry season, whale migration, perfect reef conditions, manageable crowds.
Best for budget: February. Rock-bottom prices, full waterfalls, reef still operational.
Best compromise: May. End of wet season, green landscape, falling prices, fewer stingers.
Avoid: Mid-January to mid-February if you have no tolerance for heat, humidity, and occasional road closures from flooding.
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