Best Time to Dive in Big Island / Kona
Go September to December, when the downpours ease — 4 days a month of heavy rain instead of 6. The marine life holds steady all year, so the weather picks the month.
- Best time
- Sep–Dec
- Water
- 25–27 °C
- Visibility
- 25–40 m
- Dived from
- day boat
- Tidal range
- 0.5–0.9 m
- Species logged
- 14
Where it is
111 km across · coastline from Natural Earth 10m
Diving in Big Island / Kona — 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 | Moderate | Good | Excellent | Good | Good | Poor | Poor | Poor | Moderate | Excellent | Excellent | Good |
| Water temp (°C) | 25 | 25 | 25 | 25 | 26 | 26 | 27 | 27 | 27 | 27 | 27 | 26 |
| Visibility (m) | 25–35 | 25–35 | 25–35 | 30–40 | 25–35 | 25–35 | 25–35 | 25–35 | 25–35 | 25–35 | 25–35 | 25–35 |
| Marine life | Peak | Peak | Peak | Peak | Peak | Peak | Peak | Peak | Peak | Peak | Peak | Peak |
| Best time | Peak | Peak | Peak | Peak |
Long-term averages, 2016–2025. Visibility is estimated from satellite chlorophyll-a. Water temperature is the surface mean; it is cooler at depth.
The Big Island / Kona diving season
June to August · Off season
3 months- Water temperature
- 26–27 °C
- Visibility
- 25–35 m
- Rain
- 25 days a month
Diving conditionsSeas stay mostly calm. The wind eases. It rains more.
Marine lifeReef manta (near-guaranteed), Oceanic whitetip (likely), Tiger shark (hit-or-miss) peak at Big Island / Kona in these months.
September · Shoulder season
1 month- Water temperature
- 27–27 °C
- Visibility
- 25–35 m
- Rain
- 19 days a month
Diving conditionsRain is frequent topside. The wind eases. The sea is calmer.
Marine lifeReef manta (near-guaranteed) peaks at Big Island / Kona in these months.
October to May · Peak season
8 months- Water temperature
- 25–27 °C
- Visibility
- 25–35 m
- Rain
- 16 days a month
Diving conditionsThe sea is rougher. It rains less.
Marine lifeReef manta (near-guaranteed), Whale shark (hit-or-miss), Oceanic whitetip (likely), Tiger shark (hit-or-miss) peak at Big Island / Kona in these months.
- Water temperature is satellite sea-surface temperature, so expect it cooler below the thermocline.
- Visibility is estimated from satellite chlorophyll-a.
Big Island / Kona water temperature and weather
7,500 underwater observation records · 30 surveyed years of ocean data · 10 years of sea temperature
Water & weather
Big Island / Kona 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
Seas top 1.5 m on 9% of days. Enough to cancel a day boat
Gusts over 40 km/h, about where a day boat stays in port
5 of them bring heavy rain
| Month | Swell | Gusts over 40 km/h | Wet days | Heavy rain | Air | Daylight |
|---|---|---|---|---|---|---|
| January | 2.1 m | 0% | 14 | 2 | 25 °C | 10.9 h |
| February | 1.8 m | 0% | 14 | 3 | 25 °C | 11.4 h |
| March | 1.4 m | 0% | 15 | 3 | 26 °C | 11.9 h |
| April | 1.2 m | 0% | 20 | 6 | 26 °C | 12.5 h |
| May | 1.3 m | 0% | 22 | 7 | 26 °C | 12.9 h |
| June | 1.2 m | 0% | 27 | 10 | 27 °C | 13.2 h |
| July | 1.2 m | 0% | 25 | 10 | 28 °C | 13.1 h |
| August | 1.3 m | 0% | 23 | 8 | 28 °C | 12.7 h |
| September | 1.1 m | 0% | 19 | 6 | 28 °C | 12.1 h |
| October | 1.2 m | 0% | 17 | 3 | 28 °C | 11.5 h |
| November | 1.5 m | 0% | 13 | 2 | 27 °C | 11.0 h |
| December | 1.7 m | 0% | 14 | 4 | 26 °C | 10.8 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: Good | February week 1: Good | March week 1: Good | April week 1: Good | May week 1: Moderate | June week 1: Poor | July week 1: Poor | August week 1: Poor | September week 1: Moderate | October week 1: Excellent | November week 1: Excellent | December week 1: Excellent |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Week 2 | January week 2: Moderate | February week 2: Good | March week 2: Excellent | April week 2: Good | May week 2: Good | June week 2: Poor | July week 2: Poor | August week 2: Poor | September week 2: Moderate | October week 2: Excellent | November week 2: Excellent | December week 2: Excellent |
| Week 3 | January week 3: Moderate | February week 3: Moderate | March week 3: Excellent | April week 3: Good | May week 3: Moderate | June week 3: Poor | July week 3: Poor | August week 3: Poor | September week 3: Moderate | October week 3: Excellent | November week 3: Excellent | December week 3: Moderate |
| Week 4 | January week 4: Moderate | February week 4: Good | March week 4: Excellent | April week 4: Good | May week 4: Good | June week 4: Poor | July week 4: Poor | August week 4: Poor | September week 4: Moderate | October week 4: Excellent | November week 4: Good | December week 4: Moderate |
January, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Good | 26 °C | 1.9 m | 12 km/h | 45% |
| Week 2 | Moderate | 25 °C | 2.1 m | 12 km/h | 42% |
| Week 3 | Moderate | 25 °C | 2.2 m | 12 km/h | 42% |
| Week 4 | Moderate | 25 °C | 2.1 m | 13 km/h | 46% |
February, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Good | 25 °C | 1.8 m | 13 km/h | 43% |
| Week 2 | Good | 25 °C | 1.7 m | 13 km/h | 43% |
| Week 3 | Moderate | 25 °C | 1.7 m | 12 km/h | 50% |
| Week 4 | Good | 25 °C | 1.6 m | 12 km/h | 56% |
March, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Good | 25 °C | 1.6 m | 11 km/h | 53% |
| Week 2 | Excellent | 25 °C | 1.5 m | 12 km/h | 47% |
| Week 3 | Excellent | 25 °C | 1.4 m | 12 km/h | 48% |
| Week 4 | Excellent | 25 °C | 1.3 m | 12 km/h | 53% |
April, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Good | 25 °C | 1.2 m | 12 km/h | 56% |
| Week 2 | Good | 25 °C | 1.2 m | 12 km/h | 63% |
| Week 3 | Good | 25 °C | 1.3 m | 11 km/h | 70% |
| Week 4 | Good | 25 °C | 1.2 m | 11 km/h | 73% |
May, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Moderate | 26 °C | 1.3 m | 11 km/h | 74% |
| Week 2 | Good | 26 °C | 1.3 m | 12 km/h | 70% |
| Week 3 | Moderate | 26 °C | 1.3 m | 12 km/h | 71% |
| Week 4 | Good | 26 °C | 1.2 m | 11 km/h | 74% |
June, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 26 °C | 1.2 m | 12 km/h | 79% |
| Week 2 | Poor | 26 °C | 1.2 m | 12 km/h | 89% |
| Week 3 | Poor | 26 °C | 1.2 m | 12 km/h | 89% |
| Week 4 | Poor | 27 °C | 1.2 m | 12 km/h | 86% |
July, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 27 °C | 1.1 m | 12 km/h | 84% |
| Week 2 | Poor | 27 °C | 1.2 m | 12 km/h | 79% |
| Week 3 | Poor | 27 °C | 1.3 m | 11 km/h | 81% |
| Week 4 | Poor | 27 °C | 1.2 m | 11 km/h | 79% |
August, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 27 °C | 1.2 m | 12 km/h | 74% |
| Week 2 | Poor | 27 °C | 1.2 m | 12 km/h | 75% |
| Week 3 | Poor | 27 °C | 1.3 m | 12 km/h | 77% |
| Week 4 | Poor | 27 °C | 1.3 m | 11 km/h | 73% |
September, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Moderate | 27 °C | 1.1 m | 11 km/h | 62% |
| Week 2 | Moderate | 27 °C | 1.1 m | 11 km/h | 59% |
| Week 3 | Moderate | 28 °C | 1.1 m | 11 km/h | 70% |
| Week 4 | Moderate | 27 °C | 1.1 m | 11 km/h | 71% |
October, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 27 °C | 1.1 m | 11 km/h | 65% |
| Week 2 | Excellent | 27 °C | 1.2 m | 11 km/h | 58% |
| Week 3 | Excellent | 27 °C | 1.3 m | 11 km/h | 50% |
| Week 4 | Excellent | 27 °C | 1.2 m | 11 km/h | 47% |
November, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 27 °C | 1.2 m | 11 km/h | 45% |
| Week 2 | Excellent | 27 °C | 1.4 m | 11 km/h | 41% |
| Week 3 | Excellent | 27 °C | 1.5 m | 11 km/h | 40% |
| Week 4 | Good | 27 °C | 1.6 m | 11 km/h | 43% |
December, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 26 °C | 1.6 m | 12 km/h | 40% |
| Week 2 | Excellent | 26 °C | 1.5 m | 12 km/h | 40% |
| Week 3 | Moderate | 26 °C | 1.8 m | 11 km/h | 46% |
| Week 4 | Moderate | 26 °C | 1.7 m | 11 km/h | 48% |
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: 3 mm | February: 3 mm | March: 3 mm | April: 3 mm | May: 3 mm | June: 3 mm | July: 3 mm | August: 3 mm | September: 3 mm | October: 3 mm | November: 3 mm | December: 3 mm |
One suit covers the whole year: a 3 mm full suit.
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
5 of the last 30 Julys saw a tropical storm pass within 250 km. Anything has been recorded Jul–Oct.
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
Big Island / Kona marine life — what you'll see diving
| Species | When | Observed window | Reliability | Evidence | Records |
|---|---|---|---|---|---|
| Green turtle | All year | Near-guaranteed | 1652 | ||
| Short-finned pilot whale | All year | Near-guaranteed | 1299 | ||
| Bottlenose dolphin | All year | Near-guaranteed | 274 | ||
| Spinner dolphin | All year | Near-guaranteed | 528 | ||
| Humpback whale | Jan–Feb | Near-guaranteed | 3048 | ||
| Reef manta | All year | Near-guaranteed | 385 | ||
| Ocellated eagle ray | All year | Likely | 83 | ||
| Whitetip reef shark | All year | Likely | 60 | ||
| Hawksbill turtle | All year | Likely | 18 | ||
| Whale shark | Dec–Jan, Mar, May | Hit-or-miss | 9 | ||
| Sperm whale | Apr, Oct, Dec | Likely | 68 | ||
| Oceanic whitetip | Mar–Apr, Jul, Dec | Likely | 20 | ||
| Tiger shark | May, Jul, Nov | Hit-or-miss | 12 | ||
| Yellowfin tuna | Dec–Jan, May | Hit-or-miss | 8 |
- 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 Big Island / Kona — common questions
- When is the best time to dive Big Island / Kona?
- Go September to December, when the downpours ease — 4 days a month of heavy rain instead of 6. The marine life holds steady all year, so the weather picks the month.
- When is the diving season in Big Island / Kona?
- The diving season in Big Island / Kona runs September to December.
- Is the diving in Big Island / Kona good for beginners?
- Yes. It suits Open Water divers, so it works for a first trip after certification.
- How warm is the water in Big Island / Kona?
- Between 25 and 27 °C at the surface across the year, coldest in March and warmest in September. It runs cooler below the thermocline.
- What wetsuit do I need in Big Island / Kona?
- A 3 mm full suit covers the coldest water of the year. The same suit works all year.
- What is the visibility like in Big Island / Kona?
- Roughly 25 to 40 m depending on the month. That is estimated from satellite chlorophyll-a rather than measured in the water.
- What will I see diving Big Island / Kona?
- The most consistently recorded species are Green turtle (near-guaranteed), Short-finned pilot whale (near-guaranteed) and Bottlenose dolphin (near-guaranteed), from 7,500 records within 60 km.
- Does Big Island / Kona get tropical storms?
- Yes. Over 30 years of records a storm passed within 250 km in Jul–Oct, most often in July at 5 of 30 years.
- Is there current in Big Island / Kona?
- The tide rises and falls 0.9 m around the full and new moon, against 0.5 m in between. How much of that becomes current depends on the shape of the channel.
- When should I avoid Big Island / Kona?
- July–August are the weakest months for conditions.
- How do you dive Big Island / Kona?
- Mostly from day boats. Trips run through the season, Sep–Dec.