Micronesia
Best Time to Dive in Yap
9.50°N 138.05°E
The pull is the manta cleaning stations of Mi'l Channel. It runs all year, so pick your month on the sea and the sky: April to August. The wider season runs February to August.
- Best time
- Apr–Aug
- Water
- 28–30 °C
- Visibility
- 5–25 m
- Season runs
- Feb–Aug
- Dived from
- day boat
- Tidal range
- 0.9–1.5 m
- Species logged
- 5
Worth knowing: 8 days a month of heavy rain.
Where it is
111 km across · coastline from Natural Earth 10m
Diving in Yap — 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 | Good | Excellent | Excellent | Good | Excellent | Excellent | Poor | Moderate | Poor | Good |
| Water temp (°C) | 29 | 28 | 29 | 29 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 29 |
| Visibility (m) | 10–20 | 10–20 | 10–20 | 10–20 | 10–20 | 5–15 | 10–20 | 10–20 | 10–20 | 15–25 | 10–20 | 10–20 |
| Marine life | Steady | Busy | Steady | Busy | Peak | Steady | Busy | Busy | Quiet | Steady | Quiet | Busy |
| Best time | Peak | Peak | Peak | Peak | Peak |
Excellent Good Moderate PoorPeak season Apr–Aug
Long-term averages, 2016–2025. Visibility is estimated from satellite chlorophyll-a. Water temperature is the surface mean; it is cooler at depth.
The Yap diving season
January to August · Peak season
8 monthsJFMAMJJASOND
- Water temperature
- 28–30 °C
- Visibility
- 10–20 m
- Rain
- 23 days a month
Diving conditionsExpect some swell.
September · Off season
1 monthJFMAMJJASOND
- Water temperature
- 30–30 °C
- Visibility
- 10–20 m
- Rain
- 27 days a month
Diving conditionsThe wind eases. The sea is calmer.
October to December · Shoulder season
3 monthsJFMAMJJASOND
- Water temperature
- 29–30 °C
- Visibility
- 10–20 m
- Rain
- 25 days a month
Diving conditionsThe sea is rougher.
- Spring tides run 1.5 m against 0.9 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.
Yap water temperature and weather
209 underwater observation records · 9 surveyed years of ocean data · 10 years of sea temperature
Water & weather
Yap 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
11
rough days a month
Seas top 1.5 m on 37% of days. Enough to cancel a day boat
2
blowy days a month
Gusts over 40 km/h, about where a day boat stays in port
24
wet days a month
10 of them bring heavy rain
| Month | Swell | Gusts over 40 km/h | Wet days | Heavy rain | Air | Daylight |
|---|---|---|---|---|---|---|
| January | 2.5 m | 23% | 20 | 7 | 28 °C | 11.5 h |
| February | 2.4 m | 25% | 18 | 4 | 28 °C | 11.7 h |
| March | 1.9 m | 4% | 16 | 5 | 28 °C | 11.9 h |
| April | 1.8 m | 4% | 18 | 7 | 29 °C | 12.2 h |
| May | 1.6 m | 1% | 24 | 8 | 29 °C | 12.4 h |
| June | 1.3 m | 1% | 29 | 14 | 29 °C | 12.6 h |
| July | 1.5 m | 4% | 29 | 16 | 29 °C | 12.5 h |
| August | 1.7 m | 6% | 28 | 16 | 29 °C | 12.3 h |
| September | 1.8 m | 5% | 27 | 15 | 29 °C | 12.0 h |
| October | 2.2 m | 7% | 27 | 15 | 29 °C | 11.8 h |
| November | 1.9 m | 9% | 26 | 11 | 29 °C | 11.6 h |
| December | 2.1 m | 12% | 24 | 9 | 29 °C | 11.4 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: Moderate | March week 1: Moderate | April week 1: Good | May week 1: Good | June week 1: Excellent | July week 1: Excellent | August week 1: Good | September week 1: Moderate | October week 1: Good | November week 1: Moderate | December week 1: Moderate |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Week 2 | January week 2: Good | February week 2: Excellent | March week 2: Excellent | April week 2: Good | May week 2: Good | June week 2: Good | July week 2: Good | August week 2: Good | September week 2: Poor | October week 2: Good | November week 2: Poor | December week 2: Moderate |
| Week 3 | January week 3: Poor | February week 3: Excellent | March week 3: Excellent | April week 3: Excellent | May week 3: Excellent | June week 3: Excellent | July week 3: Good | August week 3: Excellent | September week 3: Moderate | October week 3: Poor | November week 3: Poor | December week 3: Good |
| Week 4 | January week 4: Poor | February week 4: Excellent | March week 4: Excellent | April week 4: Excellent | May week 4: Excellent | June week 4: Excellent | July week 4: Good | August week 4: Excellent | September week 4: Poor | October week 4: Good | November week 4: Poor | December week 4: Good |
Excellent Good Moderate PoorBest week to go: fourth of April
January, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Good | 29 °C | 2.2 m | 35 km/h | 71% |
| Week 2 | Good | 29 °C | 2.4 m | 34 km/h | 67% |
| Week 3 | Poor | 29 °C | 2.6 m | 35 km/h | 66% |
| Week 4 | Poor | 29 °C | 2.6 m | 37 km/h | 62% |
February, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Moderate | 29 °C | 2.5 m | 37 km/h | 58% |
| Week 2 | Excellent | 29 °C | 2.4 m | 36 km/h | 60% |
| Week 3 | Excellent | 28 °C | 2.4 m | 36 km/h | 63% |
| Week 4 | Excellent | 28 °C | 2.4 m | 35 km/h | 60% |
March, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Moderate | 28 °C | 2.3 m | 33 km/h | 50% |
| Week 2 | Excellent | 29 °C | 2.0 m | 31 km/h | 47% |
| Week 3 | Excellent | 29 °C | 1.8 m | 31 km/h | 51% |
| Week 4 | Excellent | 29 °C | 1.7 m | 32 km/h | 57% |
April, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Good | 29 °C | 1.9 m | 31 km/h | 61% |
| Week 2 | Good | 29 °C | 2.3 m | 30 km/h | 62% |
| Week 3 | Excellent | 29 °C | 1.6 m | 29 km/h | 57% |
| Week 4 | Excellent | 29 °C | 1.6 m | 29 km/h | 61% |
May, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Good | 29 °C | 1.6 m | 30 km/h | 72% |
| Week 2 | Good | 29 °C | 1.6 m | 29 km/h | 75% |
| Week 3 | Excellent | 30 °C | 1.5 m | 26 km/h | 77% |
| Week 4 | Excellent | 30 °C | 1.6 m | 24 km/h | 87% |
June, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 30 °C | 1.5 m | 23 km/h | 92% |
| Week 2 | Good | 30 °C | 1.3 m | 23 km/h | 93% |
| Week 3 | Excellent | 30 °C | 1.2 m | 24 km/h | 96% |
| Week 4 | Excellent | 30 °C | 1.2 m | 23 km/h | 98% |
July, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 30 °C | 1.1 m | 22 km/h | 97% |
| Week 2 | Good | 30 °C | 1.3 m | 23 km/h | 95% |
| Week 3 | Good | 30 °C | 1.5 m | 23 km/h | 92% |
| Week 4 | Good | 30 °C | 1.9 m | 24 km/h | 94% |
August, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Good | 30 °C | 1.9 m | 24 km/h | 92% |
| Week 2 | Good | 30 °C | 1.7 m | 23 km/h | 92% |
| Week 3 | Excellent | 30 °C | 1.5 m | 21 km/h | 93% |
| Week 4 | Excellent | 30 °C | 1.7 m | 21 km/h | 87% |
September, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Moderate | 30 °C | 1.7 m | 21 km/h | 87% |
| Week 2 | Poor | 30 °C | 2.0 m | 21 km/h | 90% |
| Week 3 | Moderate | 30 °C | 2.1 m | 23 km/h | 88% |
| Week 4 | Poor | 30 °C | 1.8 m | 23 km/h | 86% |
October, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Good | 30 °C | 1.8 m | 22 km/h | 85% |
| Week 2 | Good | 30 °C | 1.9 m | 22 km/h | 88% |
| Week 3 | Poor | 30 °C | 2.2 m | 23 km/h | 89% |
| Week 4 | Good | 30 °C | 2.5 m | 24 km/h | 87% |
November, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Moderate | 30 °C | 2.4 m | 25 km/h | 90% |
| Week 2 | Poor | 30 °C | 2.1 m | 28 km/h | 90% |
| Week 3 | Poor | 30 °C | 1.9 m | 30 km/h | 81% |
| Week 4 | Poor | 30 °C | 1.8 m | 31 km/h | 79% |
December, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Moderate | 30 °C | 1.8 m | 30 km/h | 79% |
| Week 2 | Moderate | 29 °C | 1.9 m | 31 km/h | 76% |
| Week 3 | Good | 29 °C | 2.2 m | 34 km/h | 76% |
| Week 4 | Good | 29 °C | 2.2 m | 34 km/h | 75% |
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
7 of the last 30 Novembers saw a tropical storm pass within 250 km. Anything has been recorded Sep–Jan, Mar–Jul.
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
Yap marine life — what you'll see diving
| Species | When | Observed window | Reliability | Evidence | Records |
|---|---|---|---|---|---|
| Napoleon wrasse | May, Jul, Dec | Near-guaranteed | 111 | ||
| Bumphead parrotfish | Feb, May, Jul | Likely | 35 | ||
| Blacktip reef shark | Feb–Apr, Oct | Likely | 18 | ||
| Whitetip reef shark | May, Aug | Likely | 11 | ||
| Camouflage grouper | May, Dec | Hit-or-miss | 10 |
Peak Present No survey data
- 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 Yap — common questions
- When is the best time to dive Yap?
- The pull is the manta cleaning stations of Mi'l Channel. It runs all year, so pick your month on the sea and the sky: April to August. The wider season runs February to August.
- When is the diving season in Yap?
- The diving season in Yap runs February to August, and it is at its best April to August.
- Is the diving in Yap good for beginners?
- It is better with some experience. It suits Advanced Open Water divers or equivalent, so newer divers should ask the local operator which sites fit their level.
- How warm is the water in Yap?
- Between 28 and 30 °C at the surface across the year, coldest in February and warmest in June. It runs cooler below the thermocline.
- What wetsuit do I need in Yap?
- A skin or 3 mm shorty covers the coldest water of the year. The same suit works all year.
- What is the visibility like in Yap?
- Roughly 5 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 Yap?
- The most consistently recorded species are Napoleon wrasse (near-guaranteed), Bumphead parrotfish (likely) and Blacktip reef shark (likely), from 209 records within 60 km.
- Does Yap get tropical storms?
- Yes. Over 30 years of records a storm passed within 250 km in Sep–Jan, Mar–Jul, most often in November at 7 of 30 years.
- Is there current in Yap?
- The tide rises and falls 1.5 m around the full and new moon, against 0.9 m in between. How much of that becomes current depends on the shape of the channel.
- When should I avoid Yap?
- November is the weakest month for conditions.
- How do you dive Yap?
- Mostly from day boats. Trips run through the season, Feb–Aug.