Penang records about 2670mm of rain across roughly 165 wet days a year, which is a 45% chance on an average day. October is the wettest month at 380mm (14% of the annual total) and January the driest at 68mm. Local rain type: monsoon. Penang gets heavy tropical rain, especially during the northeast monsoon (October-December). The covered heritage streets of George Town provide excellent shelter.
Chance of rain on an average day: 45%
Rainfall climatology for Penang. 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 | 2670mm |
| Rain days per year | 165 |
| Odds on an average day | 45% |
| Wettest month | October — 380mm over 26 days |
| Driest month | January — 68mm over 5 days |
| Rain type | monsoon |
| Best dry window | January through March offers the driest conditions. |
| Worst rain window | October brings the heaviest monsoon rainfall. |
October delivers 459% more rain than January (380mm vs 68mm). That gap is the difference between planning around showers and ignoring them.
No single month holds more than 14% of the annual total, so rain in Penang is spread through the year — there is no season you can rely on being dry.
Penang rain arrives in short, heavy bursts — shelter and timing matter more than gear.
Rain falls on about 26 days in October against 5 in January — 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 | 68mm | 5 | 17% | 31°C |
| February | 82mm | 6 | 20% | 31°C |
| March | 145mm | 10 | 33% | 31°C |
| April | 218mm | 15 | 50% | 31°C |
| May | 240mm | 16 | 53% | 32°C |
| June | 175mm | 12 | 40% | 32°C |
| July | 185mm | 13 | 43% | 32°C |
| August | 242mm | 16 | 53% | 32°C |
| September | 355mm | 24 | 80% | 32°C |
| October | 380mm | 26 | 87% | 32°C |
| November | 235mm | 16 | 53% | 31°C |
| December | 108mm | 7 | 23% | 31°C |
Rain probability is the chance that at least 0.2mm falls at your location — not how long it rains. For Penang 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.
Penang records rain on roughly 165 days a year — about a 45% chance on any given day — totalling around 2670mm.
October, with about 380mm over 26 rain days. That is 14% of the entire year's rainfall in a single month.
January is the driest month at 68mm across roughly 5 days. January through March offers the driest conditions.
Penang gets heavy tropical rain, especially during the northeast monsoon (October-December). The covered heritage streets of George Town provide excellent shelter.
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.