Great Barrier Reef records about 1992mm of rain across roughly 90 wet days a year, which is a 25% chance on an average day. January is the wettest month at 386mm (19% of the annual total) and August the driest at 18mm. Local rain type: monsoon. The reef has a clear wet season (December-April) and dry season. Visibility is best June-October when the water is clearest.
Chance of rain on an average day: 25%
Rainfall climatology for Great Barrier Reef. The live hour-by-hour answer for today loads at the top of this page from Open-Meteo and refreshes through the day — the figures below describe a typical year, not today.
Last updated: · Live forecast data refreshes hourly.
| Annual rainfall | 1992mm |
| Rain days per year | 90 |
| Odds on an average day | 25% |
| Wettest month | January — 386mm over 21 days |
| Driest month | August — 18mm over 1 days |
| Rain type | monsoon |
| Best dry window | June through October offers the best water visibility and comfortable temperatures. |
| Worst rain window | January through March brings tropical storms with reduced underwater visibility. |
January delivers 2044% more rain than August (386mm vs 18mm). That gap is the difference between planning around showers and ignoring them.
No single month holds more than 19% of the annual total, so rain in Great Barrier Reef is spread through the year — there is no season you can rely on being dry.
Great Barrier Reef rain arrives in short, heavy bursts — shelter and timing matter more than gear.
Rain falls on about 21 days in January against 1 in August — the frequency swing matters more for planning than the millimetre totals.
Climate normals. Use them to judge whether today's live forecast at the top of the page is typical or unusual for the season.
| Month | Rainfall | Rain days | Chance on a given day | Highs |
|---|---|---|---|---|
| January | 386mm | 21 | 70% | 31°C |
| February | 370mm | 20 | 67% | 31°C |
| March | 328mm | 18 | 60% | 30°C |
| April | 168mm | 9 | 30% | 29°C |
| May | 68mm | 4 | 13% | 28°C |
| June | 38mm | 2 | 7% | 27°C |
| July | 22mm | 1 | 3% | 26°C |
| August | 18mm | 1 | 3% | 26°C |
| September | 21mm | 1 | 3% | 27°C |
| October | 35mm | 2 | 7% | 28°C |
| November | 80mm | 4 | 13% | 29°C |
| December | 128mm | 7 | 23% | 30°C |
Rain probability is the chance that at least 0.2mm falls at your location — not how long it rains. For Great Barrier Reef we combine the hourly probability curve, expected volume in millimetres, and the city's own rainfall record into a single umbrella verdict.
| Factor | Weight | What it measures |
|---|---|---|
| Hourly probability | 40% | Peak and sustained chance of measurable rain across the next 24 hours. |
| Expected volume | 30% | Total millimetres, which separates a passing shower from a genuine soaking. |
| Timing & duration | 20% | When rain starts, when it eases, and the longest continuous dry window. |
| Local rain type | 10% | Drizzle, brief showers, thunderstorms or monsoon — each needs different gear. |
Live hourly values come from Open-Meteo and refresh through the day. Monthly rainfall figures are climate normals, so they describe a typical year rather than a forecast.
Great Barrier Reef records rain on roughly 90 days a year — about a 25% chance on any given day — totalling around 1992mm.
January, with about 386mm over 21 rain days. That is 19% of the entire year's rainfall in a single month.
August is the driest month at 18mm across roughly 1 days. June through October offers the best water visibility and comfortable temperatures.
The reef has a clear wet season (December-April) and dry season. Visibility is best June-October when the water is clearest.
No. Probability is the chance that at least 0.2mm of rain falls at your location at some point in the period. Check the expected millimetres alongside it: 40% with 0.4mm is a passing shower, 40% with 12mm is a soaking.