Indonesia
Best Time to Dive in the Gili Islands
8.36°S 116.05°E
The best conditions run May to September, when the downpours ease — 1 days a month of heavy rain instead of 10. The marine life holds steady all year, so the weather picks the month. The wider season runs May to October.
- Best time
- May–Sep
- Water
- 28–30 °C
- Visibility
- 10–25 m
- Season runs
- May–Oct
- Dived from
- day boat
- Tidal range
- 0.8–1.7 m
- Species logged
- 8
Where it is
111 km across · coastline from Natural Earth 10m
Diving in the Gili Islands — monthly breakdown
A year of scuba diving conditions at a glance. Hover a month to isolate it.
| January | February | March | April | May | June | July | August | September | October | November | December | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Conditions | Poor | Poor | Poor | Moderate | Excellent | Excellent | Excellent | Excellent | Excellent | Excellent | Moderate | Poor |
| Water temp (°C) | 29 | 29 | 29 | 30 | 30 | 29 | 28 | 28 | 28 | 29 | 29 | 29 |
| Visibility (m) | 10–20 | 15–25 | 15–25 | 15–25 | 15–25 | 15–25 | 15–25 | 15–25 | 15–25 | 15–25 | 15–25 | 15–25 |
| Marine life | Steady | Busy | Busy | Busy | Busy | Busy | Busy | Busy | Busy | Busy | Steady | Steady |
| Best time | Peak | Peak | Peak | Peak | Peak |
Excellent Good Moderate PoorPeak season May–Sep
Long-term averages, 2016–2025. Visibility is estimated from satellite chlorophyll-a. Water temperature is the surface mean; it is cooler at depth.
The Gili Islands diving season
April · Shoulder season
1 monthJFMAMJJASOND
- Water temperature
- 30–30 °C
- Visibility
- 15–25 m
- Rain
- 23 days a month
Diving conditionsThis is the wet season topside. The wind eases. The sea is calmer.
May to October · Peak season
6 monthsJFMAMJJASOND
- Water temperature
- 28–30 °C
- Visibility
- 15–25 m
- Rain
- 13 days a month
Diving conditionsSeas stay mostly calm. The wind is up. It rains less.
Marine lifeReef manta (hit-or-miss) peaks at Gili Islands in these months.
November · Shoulder season
1 monthJFMAMJJASOND
- Water temperature
- 29–29 °C
- Visibility
- 15–25 m
- Rain
- 23 days a month
Diving conditionsThis is the wet season topside. The wind eases. The sea is calmer.
December to March · Off season
4 monthsJFMAMJJASOND
- Water temperature
- 29–29 °C
- Visibility
- 15–25 m
- Rain
- 27 days a month
Diving conditionsIt rains more. The sea is rougher.
Marine lifeReef manta (hit-or-miss) peaks at Gili Islands in these months.
- Spring tides run 1.7 m against 0.8 m on neaps, so currents build around the full and new moon.
- Water temperature is satellite sea-surface temperature, so expect it cooler below the thermocline.
- Visibility is estimated from satellite chlorophyll-a.
Gili Islands water temperature and weather
676 underwater observation records · 20 surveyed years of ocean data · 10 years of sea temperature
Water & weather
Gili Islands water temperature by month
The dashed line is the monthly average. Eight days in ten fall inside the band.
10th to 90th percentile rangemonthly mean
Rarely
rough enough to cancel
Seas top 1.5 m on 1% of days. Enough to cancel a day boat
0
blowy days a month
Gusts over 40 km/h, about where a day boat stays in port
19
wet days a month
6 of them bring heavy rain
| Month | Swell | Gusts over 40 km/h | Wet days | Heavy rain | Air | Daylight |
|---|---|---|---|---|---|---|
| January | 1.3 m | 0% | 27 | 14 | 29 °C | 12.4 h |
| February | 1.2 m | 0% | 28 | 15 | 29 °C | 12.3 h |
| March | 1.2 m | 0% | 28 | 10 | 30 °C | 12.1 h |
| April | 0.9 m | 0% | 23 | 7 | 30 °C | 11.8 h |
| May | 1.0 m | 0% | 16 | 2 | 30 °C | 11.6 h |
| June | 1.1 m | 0% | 12 | 1 | 30 °C | 11.5 h |
| July | 1.2 m | 0% | 9 | 0 | 30 °C | 11.6 h |
| August | 1.2 m | 0% | 9 | 0 | 30 °C | 11.7 h |
| September | 1.1 m | 0% | 14 | 1 | 31 °C | 12.0 h |
| October | 1.1 m | 0% | 16 | 3 | 31 °C | 12.2 h |
| November | 0.9 m | 0% | 23 | 7 | 31 °C | 12.4 h |
| December | 1.1 m | 0% | 27 | 13 | 30 °C | 12.5 h |
Swell is the rough end of the month: nine days in ten come in under it. Sea temperature covers 10 years, waves 4.
Pick your week
48 weeks from the daily record. Darker is better, against this site's own year. Pick a month for the detail.
| Week 1 | January week 1: Poor | February week 1: Poor | March week 1: Poor | April week 1: Moderate | May week 1: Excellent | June week 1: Excellent | July week 1: Excellent | August week 1: Excellent | September week 1: Excellent | October week 1: Excellent | November week 1: Moderate | December week 1: Poor |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Week 2 | January week 2: Poor | February week 2: Poor | March week 2: Poor | April week 2: Moderate | May week 2: Excellent | June week 2: Excellent | July week 2: Excellent | August week 2: Excellent | September week 2: Excellent | October week 2: Excellent | November week 2: Moderate | December week 2: Poor |
| Week 3 | January week 3: Poor | February week 3: Poor | March week 3: Poor | April week 3: Moderate | May week 3: Excellent | June week 3: Excellent | July week 3: Excellent | August week 3: Excellent | September week 3: Excellent | October week 3: Excellent | November week 3: Moderate | December week 3: Poor |
| Week 4 | January week 4: Poor | February week 4: Poor | March week 4: Moderate | April week 4: Moderate | May week 4: Excellent | June week 4: Excellent | July week 4: Excellent | August week 4: Excellent | September week 4: Excellent | October week 4: Excellent | November week 4: Moderate | December week 4: Poor |
Excellent Good Moderate PoorBest week to go: fourth of June
January, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 29 °C | 1.4 m | 13 km/h | 85% |
| Week 2 | Poor | 29 °C | 1.2 m | 13 km/h | 82% |
| Week 3 | Poor | 29 °C | 1.2 m | 14 km/h | 87% |
| Week 4 | Poor | 29 °C | 1.4 m | 14 km/h | 95% |
February, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 28 °C | 1.4 m | 14 km/h | 99% |
| Week 2 | Poor | 29 °C | 1.3 m | 14 km/h | 96% |
| Week 3 | Poor | 29 °C | 1.1 m | 14 km/h | 94% |
| Week 4 | Poor | 29 °C | 1.1 m | 13 km/h | 94% |
March, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 29 °C | 1.2 m | 13 km/h | 91% |
| Week 2 | Poor | 29 °C | 1.3 m | 13 km/h | 87% |
| Week 3 | Poor | 29 °C | 1.3 m | 12 km/h | 88% |
| Week 4 | Moderate | 29 °C | 1.0 m | 12 km/h | 90% |
April, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Moderate | 29 °C | 0.8 m | 12 km/h | 90% |
| Week 2 | Moderate | 30 °C | 0.9 m | 11 km/h | 84% |
| Week 3 | Moderate | 30 °C | 1.1 m | 10 km/h | 72% |
| Week 4 | Moderate | 30 °C | 0.9 m | 10 km/h | 64% |
May, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 30 °C | 0.9 m | 11 km/h | 60% |
| Week 2 | Excellent | 30 °C | 1.0 m | 11 km/h | 53% |
| Week 3 | Excellent | 29 °C | 1.0 m | 11 km/h | 47% |
| Week 4 | Excellent | 29 °C | 1.0 m | 12 km/h | 45% |
June, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 29 °C | 1.1 m | 12 km/h | 44% |
| Week 2 | Excellent | 29 °C | 1.1 m | 11 km/h | 46% |
| Week 3 | Excellent | 29 °C | 1.0 m | 12 km/h | 43% |
| Week 4 | Excellent | 29 °C | 1.0 m | 13 km/h | 35% |
July, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 29 °C | 1.0 m | 14 km/h | 34% |
| Week 2 | Excellent | 28 °C | 1.2 m | 14 km/h | 33% |
| Week 3 | Excellent | 28 °C | 1.1 m | 14 km/h | 24% |
| Week 4 | Excellent | 28 °C | 1.2 m | 15 km/h | 23% |
August, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 28 °C | 1.2 m | 15 km/h | 30% |
| Week 2 | Excellent | 28 °C | 1.2 m | 14 km/h | 34% |
| Week 3 | Excellent | 28 °C | 1.1 m | 15 km/h | 27% |
| Week 4 | Excellent | 28 °C | 1.1 m | 16 km/h | 22% |
September, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 28 °C | 1.2 m | 15 km/h | 33% |
| Week 2 | Excellent | 28 °C | 1.2 m | 15 km/h | 46% |
| Week 3 | Excellent | 28 °C | 1.1 m | 15 km/h | 54% |
| Week 4 | Excellent | 29 °C | 1.1 m | 15 km/h | 55% |
October, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 29 °C | 1.1 m | 15 km/h | 49% |
| Week 2 | Excellent | 29 °C | 1.1 m | 16 km/h | 46% |
| Week 3 | Excellent | 29 °C | 1.0 m | 17 km/h | 53% |
| Week 4 | Excellent | 29 °C | 1.0 m | 16 km/h | 59% |
November, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Moderate | 29 °C | 1.0 m | 14 km/h | 64% |
| Week 2 | Moderate | 29 °C | 0.9 m | 14 km/h | 73% |
| Week 3 | Moderate | 29 °C | 0.9 m | 14 km/h | 78% |
| Week 4 | Moderate | 29 °C | 0.9 m | 14 km/h | 84% |
December, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 29 °C | 1.0 m | 15 km/h | 85% |
| Week 2 | Poor | 29 °C | 1.1 m | 15 km/h | 86% |
| Week 3 | Poor | 29 °C | 1.1 m | 16 km/h | 86% |
| Week 4 | Poor | 29 °C | 1.4 m | 15 km/h | 87% |
10 years of daily records, averaged into weeks.
Gear & storms
What to wear
Off the coldest water of each month, not the average — that is what the suit has to cope with.
| January | February | March | April | May | June | July | August | September | October | November | December | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Suit | January: skin | February: skin | March: skin | April: skin | May: skin | June: skin | July: skin | August: skin | September: skin | October: skin | November: skin | December: skin |
One suit covers the whole year: a skin or 3 mm shorty.
Swell through the year
The rough end of each month — nine days in ten come in under it.
Amber is over 1.5 m.
Tides
Tropical storms
1 of the last 30 Aprils saw a tropical storm pass within 250 km. April is the only month with a recorded pass.
Share of the last 30 years with a storm that month.
- NOAASea surface temperature, from OISST and MUR
- ERA5Wind, waves, rain and air temperature, via Open-Meteo
- OBISMarine species records within 60 km
- IBTrACSTropical cyclone tracks, 1996 to 2025
Gili Islands marine life — what you'll see diving
| Species | When | Observed window | Reliability | Evidence | Records |
|---|---|---|---|---|---|
| Hawksbill turtle | All year | Near-guaranteed | 224 | ||
| Green turtle | All year | Near-guaranteed | 263 | ||
| Whitetip reef shark | All year | Near-guaranteed | 68 | ||
| Bluespotted ribbontail ray | All year | Near-guaranteed | 35 | ||
| Napoleon wrasse | Jun–Jul, Sep–Oct | Likely | 12 | ||
| Bumphead parrotfish | Mar, Jun–Aug | Likely | 13 | ||
| Bigeye trevally | Apr–May, Oct | Likely | 14 | ||
| Reef manta | Feb, Jun, Sep | Hit-or-miss | 14 |
Peak Present
- Observed window
- Months with records. Peak is where most of them fall.
- Reliability
- Near-guaranteed in 60% of surveyed years or more
- Likely 30% to 60%
- Hit-or-miss under 30%
- Evidence
- Years it was seen, out of the years anyone surveyed.
- Records
- OBIS sightings within 60 km.
These are sightings people logged, not a full survey of the reef. A species missing from a month may just mean nobody recorded one.
Diving the Gili Islands — common questions
- When is the best time to dive the Gili Islands?
- The best conditions run May to September, when the downpours ease — 1 days a month of heavy rain instead of 10. The marine life holds steady all year, so the weather picks the month. The wider season runs May to October.
- When is the diving season at the Gili Islands?
- The diving season at the Gili Islands runs May to October, and it is at its best May to September.
- Is the diving at the Gili Islands good for beginners?
- Yes. It suits Open Water divers, so it works for a first trip after certification.
- How warm is the water at the Gili Islands?
- Between 28 and 30 °C at the surface across the year, coldest in August and warmest in April. It runs cooler below the thermocline.
- What wetsuit do I need at the Gili Islands?
- A skin or 3 mm shorty covers the coldest water of the year. The same suit works all year.
- What is the visibility like at the Gili Islands?
- Roughly 10 to 25 m depending on the month. That is estimated from satellite chlorophyll-a rather than measured in the water.
- What will I see diving the Gili Islands?
- The most consistently recorded species are Hawksbill turtle (near-guaranteed), Green turtle (near-guaranteed) and Whitetip reef shark (near-guaranteed), from 676 records within 60 km.
- Does the Gili Islands get tropical storms?
- Yes. Over 30 years of records a storm passed within 250 km in Apr, most often in April at 1 of 30 years.
- Is there current at the Gili Islands?
- The tide rises and falls 1.7 m around the full and new moon, against 0.8 m in between. How much of that becomes current depends on the shape of the channel.
- When should I avoid the Gili Islands?
- December–February are the weakest months for conditions.
- How do you dive the Gili Islands?
- Mostly from day boats. Trips run through the season, May–Oct.