Tonga records about 1780mm of rain across roughly 112 wet days a year, which is a 31% chance on an average day. March is the wettest month at 192mm (11% of the annual total) and July the driest at 72mm. Local rain type: brief showers. Tonga has a tropical wet/dry season. Cyclone risk exists from November through April — the dry season (May-October) is ideal for visiting.
Chance of rain on an average day: 31%
Rainfall climatology for Tonga. 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.
Conditions on this page are recalculated from the latest forecast every time it is opened, for the current date in the location's own time zone. Showing .
| Annual rainfall | 1780mm |
| Rain days per year | 112 |
| Odds on an average day | 31% |
| Wettest month | March — 192mm over 15 days |
| Driest month | July — 72mm over 6 days |
| Rain type | brief showers |
| Best dry window | June through October offers the driest, most comfortable conditions. |
| Worst rain window | January through March brings the highest cyclone risk and heaviest rainfall. |
March delivers 167% more rain than July (192mm vs 72mm). That gap is the difference between planning around showers and ignoring them.
No single month holds more than 11% of the annual total, so rain in Tonga is spread through the year — there is no season you can rely on being dry.
Tonga rain typically comes as discrete showers, so a compact umbrella and a flexible plan are usually enough.
Rain falls on about 15 days in March against 6 in July — 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 | 185mm | 15 | 50% | 29°C |
| February | 168mm | 14 | 47% | 29°C |
| March | 192mm | 15 | 50% | 28°C |
| April | 140mm | 11 | 37% | 27°C |
| May | 102mm | 8 | 27% | 26°C |
| June | 82mm | 7 | 23% | 25°C |
| July | 72mm | 6 | 20% | 24°C |
| August | 78mm | 6 | 20% | 24°C |
| September | 72mm | 6 | 20% | 25°C |
| October | 82mm | 7 | 23% | 26°C |
| November | 88mm | 7 | 23% | 27°C |
| December | 128mm | 10 | 33% | 28°C |
Rain probability is the chance that at least 0.2mm falls at your location — not how long it rains. For Tonga 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.
Tonga records rain on roughly 112 days a year — about a 31% chance on any given day — totalling around 1780mm.
March, with about 192mm over 15 rain days. That is 11% of the entire year's rainfall in a single month.
July is the driest month at 72mm across roughly 6 days. June through October offers the driest, most comfortable conditions.
Tonga has a tropical wet/dry season. Cyclone risk exists from November through April — the dry season (May-October) is ideal for visiting.
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.