Best time to dive Northern GBR & Coral Sea
Diveable year-round; best visibility and least wind/rain August–December. Dwarf minke whales visit the Ribbon Reefs mostly in June–July (about 90% of sightings; occasional March–October); mantas and hammerheads in the Coral Sea April–September; coral spawning November/December. Winter trade winds can reach 25 knots; summer is the wet/cyclone season.
Peak season: June–October
Book a Northern GBR & Coral Sea LiveaboardUpcoming departures on DivebookerOverall diving, month by month
Balanced scoring · forecasts include the 2026/27 El Niño outlook
Confidence: Nov medium · Dec medium · Jan medium · Feb medium · Mar medium · Apr medium · May medium · Jun medium · Jul medium · Aug medium · Sep medium · Oct low · Nov low · Dec low
What's good when
Each attribute scored 0–10 for every month
| Nov2026 | Dec | Jan2027 | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Pelagic & big animals | 7 | 7 | 7 | 7 | 7 | 7 | 8 | 9 | 9 | 8 | 8 | 8 | 7 | 7 |
| Macro life | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 |
| Coral & reef health | 5 | 5 | 4 | 4 | 4 | 4 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 |
| Visibility | 9 | 8 | 7 | 6 | 7 | 8 | 8 | 8 | 8 | 9 | 9 | 9 | 9 | 8 |
| Water temperature | 9 | 10 | 10 | 10 | 10 | 10 | 8 | 7 | 7 | 7 | 7 | 8 | 9 | 10 |
| Weather & sea state | 9 | 7 | 5 | 5 | 5 | 7 | 7 | 7 | 7 | 8 | 9 | 9 | 9 | 7 |
| Operations & access | 10 | 9 | 8 | 7 | 8 | 9 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 9 |
Climate outlook
How this year's forecast differs from a typical year
- Coral & reef health -1.3 · Reefs recovering from El Niño summer bleaching (Nov 2026 – December 2027)
- Coral & reef health -2.3 · El Niño summer marine heatwave; very high mass-bleaching risk (Jan 2027 – April 2027)
Water temperature & visibility
| Month | Water | Visibility |
|---|---|---|
| November 2026 | 27.5 °C (82 °F) | 25–35 m |
| December 2026 | 29.0 °C (84 °F) | 20–30 m |
| January 2027 | 29.5 °C (85 °F) | 15–25 m |
| February 2027 | 29.5 °C (85 °F) | 15–20 m |
| March 2027 | 29.0 °C (84 °F) | 15–25 m |
| April 2027 | 28.0 °C (82 °F) | 20–30 m |
| May 2027 | 26.5 °C (80 °F) | 20–30 m |
| June 2027 | 25.0 °C (77 °F) | 20–30 m |
| July 2027 | 24.5 °C (76 °F) | 20–30 m |
| August 2027 | 24.5 °C (76 °F) | 25–35 m |
| September 2027 | 25.0 °C (77 °F) | 25–40 m |
| October 2027 | 26.0 °C (79 °F) | 25–40 m |
| November 2027 | 27.5 °C (82 °F) | 25–35 m |
| December 2027 | 29.0 °C (84 °F) | 20–30 m |
Marine life calendar
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| dwarf minke whale | ● | ● | ● | Peak | Peak | ● | ● | ● | ||||
| potato cod | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● |
| grey reef shark | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● |
| coral spawning | Peak | ● | ||||||||||
| manta ray | ● | ● | ● | ● | ● | ● |
Peak = best odds · ● = regularly seen · blank = unlikely. Calendar months, every year.
About the diving
- Difficulty
- Beginner
- Current strength
- 2 / 5
- Luxury level
- 5 / 5
- Typical depth
- 5–30 m
- Max depth of interest
- 40 m
- Dive styles
- Liveaboard, Day boat
- Suggested certification
- Open Water (Osprey wall dives: Advanced)
- Nearest airport
- CNS
- Snorkelling
- Good
- Known for
- dwarf minke whale, potato cod, grey reef shark, manta ray
Famous sites: Cod Hole · Steve's Bommie · North Horn (Osprey) · Pixie Pinnacle
Season notes & sources
- Diveable year-round; best visibility and least wind/rain August–December. Dwarf minke whales visit the Ribbon Reefs mostly in June–July (about 90% of sightings; occasional March–October); mantas and hammerheads in the Coral Sea April–September; coral spawning November/December. Winter trade winds can reach 25 knots; summer is the wet/cyclone season.
- Coral cover fell in the 2024–25 bleaching (the sixth mass bleaching since 2016); scientists warned in July 2026 of a very high mass-bleaching risk from the 2026/27 El Niño.