Lombok Weather Month by Month: Complete Climate Data

Lombok has a tropical savanna climate (Koppen classification Aw), characterized by warm temperatures year-round, a distinct dry season, and a distinct wet season. The island sits at approximately 8.5 degrees south latitude — firmly in the tropics — which means relatively consistent day length (about 12 hours of daylight year-round) and intense equatorial sun.

The climate is influenced by two dominant weather systems:

Southeast Monsoon (May-September): Dry air from the Australian continent flows northward across the Lesser Sunda Islands, bringing minimal rainfall, lower humidity, and consistent offshore winds. This produces Lombok's dry season.

Northwest Monsoon (October-April): Warm, moisture-laden air from the South China Sea and Indian Ocean flows southward, bringing heavy rainfall, high humidity, and variable winds. This produces the wet season.

The transition periods between monsoons (April-May and October-November) create shoulder seasons with mixed conditions — typically drier than wet season but less reliably sunny than peak dry season.

| Month | Avg High | Avg Low | Rain (mm) | Rainy Days | Humidity | Sea Temp | Diving Vis |

|-------|----------|---------|-----------|------------|----------|----------|-----------|

| Jan | 31°C | 24°C | 250 | 17 | 85-90% | 29°C | 10-15m |

| Feb | 31°C | 24°C | 280 | 18 | 85-95% | 29°C | 10-15m |

| Mar | 31°C | 24°C | 200 | 15 | 80-90% | 29°C | 12-18m |

| Apr | 32°C | 24°C | 100 | 10 | 75-85% | 29°C | 15-20m |

| May | 31°C | 23°C | 50 | 5 | 70-80% | 28°C | 18-25m |

| Jun | 30°C | 22°C | 30 | 3 | 65-75% | 27°C | 20-28m |

| Jul | 29°C | 22°C | 20 | 2 | 60-70% | 26°C | 25-30m |

| Aug | 30°C | 22°C | 15 | 1 | 60-70% | 26°C | 25-30m |

| Sep | 31°C | 22°C | 30 | 3 | 65-75% | 27°C | 20-28m |

| Oct | 32°C | 23°C | 80 | 8 | 70-80% | 28°C | 15-22m |

| Nov | 33°C | 24°C | 150 | 12 | 80-85% | 29°C | 12-18m |

| Dec | 32°C | 24°C | 200 | 15 | 80-90% | 29°C | 10-15m |

Data represents coastal lowland conditions. Mountain areas are cooler with higher rainfall.

### Coastal Lowlands

Lombok's coastal temperatures are remarkably consistent year-round. The difference between the "coolest" month (July, 29 degrees C high) and the "warmest" (November, 33 degrees C high) is just 4 degrees. For practical purposes, it is warm every day of the year.

The perceived temperature varies more than the actual thermometer reading. Dry season at 30 degrees C with 65% humidity feels comfortable. Wet season at 31 degrees C with 90% humidity feels oppressively hot. Humidity is the real variable affecting comfort.

### Daily Patterns

Temperature follows a predictable daily cycle:

• Sunrise (6 AM): 22-24 degrees C — the coolest time of day
• Morning (9 AM): 27-29 degrees C — pleasant for activities
• Midday (12 PM): 30-33 degrees C — peak heat, seek shade
• Afternoon (3 PM): 29-32 degrees C — still hot, particularly if humid
• Evening (7 PM): 26-28 degrees C — cooling for dinner outdoors
• Night (10 PM): 23-25 degrees C — comfortable sleeping temperature

### Altitude Effects

Temperature drops approximately 6 degrees C for every 1,000 meters of elevation gain. This makes a dramatic difference on Mount Rinjani:

| Location | Elevation | Typical Night Temp (Dry Season) |

|----------|-----------|-------------------------------|

| Coast (Kuta, Senggigi) | Sea level | 22-24°C |

| Senaru village | 600m | 18-20°C |

| Rinjani crater rim | 2,641m | 5-10°C |

| Rinjani summit | 3,726m | 0-5°C |

Trekkers who pack only tropical clothing for Rinjani are in for a cold, miserable night. Warm layers, a sleeping bag, and a hat and gloves are essential for summit attempts.

### Annual Rainfall

Lombok receives approximately 1,500-2,000mm of rainfall annually, with over 80% concentrated in the wet season (October-April). For comparison, London receives about 600mm and Singapore about 2,400mm.

### Wet Season Rain Character

Wet season rain in Lombok is convective — heated by the morning sun, moisture rises and condenses into massive cumulonimbus clouds that release their water in intense, short-duration downpours. A typical wet season rain event dumps 20-40mm in 1-2 hours, then clears. This is fundamentally different from the steady, all-day drizzle common in temperate climates.

Lightning accompanies most wet season storms. Lombok's tropical thunderstorms are dramatic — forked lightning across the sky, rolling thunder, and sheets of rain visible across the ocean. Impressive from a covered terrace, less fun on a scooter.

### Dry Season Rain

Dry season rainfall is negligible. June through August may have only 1-2 brief showers in the entire three-month period. When dry season rain does occur, it is light and short — a 10-minute sprinkle rather than a drenching downpour. You can reliably plan outdoor activities during dry season without rain contingencies.

### Regional Variations

The west and north sides of Lombok (Senggigi, north coast) receive slightly more rainfall than the south coast (Kuta) due to orographic effects — moisture-laden winds hit the central mountains and dump rain on the windward side. The south coast sits in a partial rain shadow, making it slightly drier overall.

Mount Rinjani creates its own weather patterns. Cloud formation begins by mid-morning most days, and afternoon rain on the mountain is common even during the dry season. This affects Rinjani trekkers who should plan to reach exposed sections (crater rim, summit) in the early morning before clouds build.

### Water Temperature

Lombok's sea temperature ranges from 26-30 degrees C throughout the year — warm enough for comfortable swimming, snorkeling, and diving at any time. The variation is small: wet season water is 2-3 degrees warmer than dry season.

A thin wetsuit (2-3mm shortie) is helpful for divers doing multiple dives in the cooler dry season months (July-August) when water temperature drops to 26 degrees C and wind chill on the boat between dives can be cool.

### Wave Conditions

The south coast faces the Indian Ocean and receives swell energy from storms in the Southern Hemisphere. Wave conditions are seasonal:

• Dry season (May-Sep): Consistent south swells of 3-8 feet. Clean conditions with offshore winds. Best for intermediate surfers and reliable surf sessions.
• Wet season (Oct-Apr): Larger, more powerful swells of 4-12 feet. Onshore winds create choppy surface conditions. Best for experienced surfers seeking bigger waves.
• Transition months (Apr, Oct): Variable conditions with mixing swell directions. Can produce excellent windows.

The north coast (Senggigi, Gili Islands) is largely sheltered from the south swell and has calmer conditions year-round, making it better for swimming and snorkeling.

### Tidal Patterns

Lombok experiences mixed semi-diurnal tides with two unequal high tides and two unequal low tides per day. Tidal range is moderate (1-2 meters). Tide timing affects:

• Reef access for snorkeling (some reefs are too shallow at low tide)
• Surf break quality (many reef breaks work best at specific tide stages)
• Beach size (some beaches nearly disappear at high tide)

Check tide charts for your dates — local surf shops and dive operators post daily tide information.

| Month | Swell Size | Consistency | Wind | Best Spots | Level |

|-------|-----------|-------------|------|-----------|-------|

| Jan | 4-8 ft | Moderate | Onshore | Gerupuk, Ekas | Advanced |

| Feb | 4-10 ft | Good | Onshore | Desert Point, Gerupuk | Advanced |

| Mar | 3-8 ft | Moderate | Variable | Gerupuk, Selong Belanak | All levels |

| Apr | 3-6 ft | Building | Shifting offshore | All south coast | All levels |

| May | 3-6 ft | Good | Offshore | All south coast | All levels |

| Jun | 4-8 ft | Very good | Offshore | Desert Point, Gerupuk | Int-Advanced |

| Jul | 4-8 ft | Excellent | Offshore | Desert Point, Gerupuk, Ekas | Int-Advanced |

| Aug | 4-8 ft | Excellent | Offshore | All south coast | All levels |

| Sep | 3-6 ft | Good | Offshore | All south coast | All levels |

| Oct | 3-6 ft | Declining | Shifting | Gerupuk, Selong Belanak | All levels |

| Nov | 3-8 ft | Variable | Onshore | Gerupuk, Ekas | Intermediate+ |

| Dec | 4-8 ft | Variable | Onshore | Gerupuk, Ekas | Advanced |

| Month | Visibility | Water Temp | Current | Highlight |

|-------|-----------|-----------|---------|-----------|

| Jan | 10-15m | 29°C | Moderate | Macro season |

| Feb | 10-15m | 29°C | Moderate | Macro season |

| Mar | 12-18m | 29°C | Moderate | Conditions improving |

| Apr | 15-20m | 29°C | Mild | Good all-round diving |

| May | 18-25m | 28°C | Mild | Visibility climbing |

| Jun | 20-28m | 27°C | Mild | Excellent reef diving |

| Jul | 25-30m | 26°C | Mild | Peak visibility |

| Aug | 25-30m | 26°C | Mild | Peak visibility, manta start |

| Sep | 20-28m | 27°C | Mild-Moderate | Manta season building |

| Oct | 15-22m | 28°C | Moderate | Manta peak, mantas + plankton |

| Nov | 12-18m | 29°C | Moderate-Strong | Large pelagics, manta tail end |

| Dec | 10-15m | 29°C | Moderate | Reduced visibility, macro |

### South Lombok (Kuta, Selong Belanak)

Slightly drier than other regions due to partial rain shadow effect from central mountains. Benefits from consistent south coast sea breezes. Clear mornings even during wet season. Best all-round weather for tourists.

### West Lombok (Senggigi, Mataram)

Receives slightly more rainfall than the south coast. The coastal strip benefits from sea breezes but inland areas (Mataram) can feel hotter and more humid. Senggigi's northwest-facing coast gets shelter from south swells, creating calm swimming conditions year-round.

### North Lombok (Senaru, Sembalun)

Wetter than lowland areas due to orographic rainfall from the Rinjani massif. Cooler temperatures at village elevations (500-700m). Cloud cover builds quickly during the day, especially in wet season. More rain days than the coast, even during dry season.

### Gili Islands

The Gili Islands have a microclimate that is slightly drier than mainland Lombok due to their low elevation and surrounded-by-ocean position. Sea breezes moderate temperatures. However, the islands have zero freshwater sources and depend on desalination and rainwater collection, which limits water availability during extended dry periods.

### East Lombok

Less visited by tourists and less well documented climatically. Generally similar to south Lombok patterns but with slightly higher rainfall in mountain-adjacent areas. Coastal areas follow the dry/wet season pattern reliably.

The weather data in this guide represents averages. Individual years can vary — El Nino events tend to produce drier-than-normal dry seasons and delayed wet seasons, while La Nina events intensify the wet season. Climate patterns are shifting generally toward more variable conditions, making precise prediction more difficult than historical averages suggest.