Best Time to Dive in the Channel Islands
Plan for June to October once the water has warmed to 19 °C from 15. The marine life holds steady all year, so the weather picks the month.
- Best time
- Jun–Oct
- Water
- 14–20 °C
- Visibility
- 10–25 m
- Dived from
- liveaboard and day boat
- Tidal range
- 1.1–2.2 m
- Species logged
- 13
Worth knowing: water around 17 °C.
Where it is
111 km across · coastline from Natural Earth 10m
Diving in the Channel 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 | Poor | Moderate | Good | Excellent | Excellent | Excellent | Excellent | Moderate | Poor |
| Water temp (°C) | 15 | 14 | 14 | 14 | 16 | 17 | 19 | 20 | 20 | 19 | 17 | 16 |
| Visibility (m) | 15–25 | 15–25 | 10–20 | 10–20 | 10–20 | 10–20 | 15–25 | 15–25 | 15–25 | 15–25 | 15–25 | 15–25 |
| Marine life | Peak | Peak | Peak | Peak | Peak | Peak | Peak | Peak | Peak | Peak | Peak | Peak |
| Best time | Peak | 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 Channel Islands diving season
May · Shoulder season
1 month- Water temperature
- 16–16 °C
- Visibility
- 10–20 m
- Rain
- 1 days a month
Diving conditionsSeas stay mostly calm. It rains less.
Marine lifeCalifornia sea lion (near-guaranteed) peaks at Channel Islands in these months.
June to October · Peak season
5 months- Water temperature
- 17–20 °C
- Visibility
- 15–25 m
- Rain
- 1 days a month
Diving conditionsSeas stay mostly calm. It rains less. The wind eases.
Marine lifeOcean sunfish (near-guaranteed), Blue shark (near-guaranteed), Sardine (near-guaranteed), California sea lion (near-guaranteed) peak at Channel Islands in these months.
November · Shoulder season
1 month- Water temperature
- 17–17 °C
- Visibility
- 15–25 m
- Rain
- 3 days a month
Diving conditionsSeas stay mostly calm. It rains more.
Marine lifeCalifornia sea lion (near-guaranteed) peaks at Channel Islands in these months.
December to April · Off season
5 months- Water temperature
- 14–16 °C
- Visibility
- 15–25 m
- Rain
- 5 days a month
Diving conditionsExpect some swell. It rains more. The wind is up.
Marine lifeCalifornia sea lion (near-guaranteed) peaks at Channel Islands in these months.
- Spring tides run 2.2 m against 1.1 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.
Channel Islands water temperature and weather
8,721 underwater observation records · 32 surveyed years of ocean data · 10 years of sea temperature
Water & weather
Channel 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
Seas top 2.5 m on under 1% of days. Enough to cancel a liveaboard crossing
Gusts over 40 km/h, about where a day boat stays in port
1 of them bring heavy rain
| Month | Swell | Gusts over 40 km/h | Wet days | Heavy rain | Air | Daylight |
|---|---|---|---|---|---|---|
| January | 1.9 m | 25% | 6 | 3 | 16 °C | 10.0 h |
| February | 2.1 m | 30% | 5 | 2 | 15 °C | 10.8 h |
| March | 1.9 m | 34% | 7 | 3 | 15 °C | 11.7 h |
| April | 1.8 m | 31% | 2 | 0 | 16 °C | 12.9 h |
| May | 1.5 m | 22% | 1 | 0 | 16 °C | 13.8 h |
| June | 1.2 m | 11% | 0 | 0 | 18 °C | 14.3 h |
| July | 1.0 m | 1% | 0 | 0 | 20 °C | 14.1 h |
| August | 1.1 m | 0% | 1 | 0 | 20 °C | 13.3 h |
| September | 1.2 m | 6% | 1 | 0 | 21 °C | 12.2 h |
| October | 1.4 m | 14% | 1 | 0 | 20 °C | 11.1 h |
| November | 1.5 m | 18% | 3 | 1 | 18 °C | 10.2 h |
| December | 1.6 m | 24% | 5 | 2 | 16 °C | 9.7 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: Poor | May week 1: Poor | June week 1: Good | July week 1: Excellent | August week 1: Excellent | September week 1: Excellent | October week 1: Excellent | November week 1: Good | December week 1: Moderate |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Week 2 | January week 2: Poor | February week 2: Poor | March week 2: Poor | April week 2: Poor | May week 2: Poor | 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: Moderate |
| Week 3 | January week 3: Poor | February week 3: Poor | March week 3: Poor | April week 3: Moderate | May week 3: Moderate | June week 3: Excellent | July week 3: Excellent | August week 3: Excellent | September week 3: Excellent | October week 3: Excellent | November week 3: Poor | December week 3: Poor |
| Week 4 | January week 4: Poor | February week 4: Poor | March week 4: Poor | April week 4: Moderate | May week 4: Good | June week 4: Excellent | July week 4: Excellent | August week 4: Excellent | September week 4: Excellent | October week 4: Good | November week 4: Poor | December week 4: Poor |
January, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 15 °C | 2.1 m | 29 km/h | 24% |
| Week 2 | Poor | 15 °C | 2.0 m | 28 km/h | 21% |
| Week 3 | Poor | 15 °C | 1.5 m | 28 km/h | 18% |
| Week 4 | Poor | 15 °C | 1.5 m | 27 km/h | 16% |
February, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 15 °C | 1.8 m | 27 km/h | 19% |
| Week 2 | Poor | 15 °C | 2.1 m | 29 km/h | 19% |
| Week 3 | Poor | 14 °C | 2.1 m | 31 km/h | 18% |
| Week 4 | Poor | 14 °C | 2.0 m | 30 km/h | 20% |
March, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 14 °C | 2.1 m | 29 km/h | 25% |
| Week 2 | Poor | 14 °C | 1.9 m | 31 km/h | 28% |
| Week 3 | Poor | 14 °C | 1.9 m | 32 km/h | 22% |
| Week 4 | Poor | 14 °C | 2.0 m | 34 km/h | 14% |
April, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 14 °C | 1.9 m | 33 km/h | 11% |
| Week 2 | Poor | 14 °C | 1.7 m | 31 km/h | 8% |
| Week 3 | Moderate | 14 °C | 1.6 m | 31 km/h | 4% |
| Week 4 | Moderate | 15 °C | 1.6 m | 31 km/h | 4% |
May, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 15 °C | 1.5 m | 27 km/h | 4% |
| Week 2 | Poor | 15 °C | 1.7 m | 27 km/h | 3% |
| Week 3 | Moderate | 16 °C | 1.4 m | 28 km/h | 2% |
| Week 4 | Good | 16 °C | 1.1 m | 24 km/h | 1% |
June, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Good | 16 °C | 1.1 m | 20 km/h | 1% |
| Week 2 | Excellent | 17 °C | 1.2 m | 21 km/h | 1% |
| Week 3 | Excellent | 18 °C | 1.4 m | 21 km/h | 1% |
| Week 4 | Excellent | 18 °C | 1.2 m | 20 km/h | 0% |
July, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 18 °C | 1.1 m | 21 km/h | 0% |
| Week 2 | Excellent | 19 °C | 1.0 m | 20 km/h | 0% |
| Week 3 | Excellent | 19 °C | 1.0 m | 20 km/h | 0% |
| Week 4 | Excellent | 20 °C | 1.0 m | 21 km/h | 1% |
August, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 20 °C | 1.1 m | 22 km/h | 2% |
| Week 2 | Excellent | 20 °C | 1.1 m | 21 km/h | 2% |
| Week 3 | Excellent | 20 °C | 1.0 m | 20 km/h | 2% |
| Week 4 | Excellent | 20 °C | 1.0 m | 21 km/h | 2% |
September, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 20 °C | 1.1 m | 22 km/h | 2% |
| Week 2 | Excellent | 20 °C | 1.2 m | 22 km/h | 3% |
| Week 3 | Excellent | 20 °C | 1.2 m | 22 km/h | 4% |
| Week 4 | Excellent | 20 °C | 1.1 m | 21 km/h | 4% |
October, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 19 °C | 1.1 m | 20 km/h | 3% |
| Week 2 | Excellent | 19 °C | 1.3 m | 21 km/h | 4% |
| Week 3 | Excellent | 19 °C | 1.3 m | 23 km/h | 4% |
| Week 4 | Good | 18 °C | 1.4 m | 22 km/h | 4% |
November, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Good | 18 °C | 1.5 m | 22 km/h | 6% |
| Week 2 | Moderate | 17 °C | 1.5 m | 23 km/h | 9% |
| Week 3 | Poor | 17 °C | 1.5 m | 25 km/h | 12% |
| Week 4 | Poor | 16 °C | 1.2 m | 24 km/h | 14% |
December, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Moderate | 16 °C | 1.3 m | 24 km/h | 15% |
| Week 2 | Moderate | 16 °C | 1.5 m | 26 km/h | 11% |
| Week 3 | Poor | 15 °C | 1.6 m | 27 km/h | 14% |
| Week 4 | Poor | 15 °C | 1.8 m | 28 km/h | 23% |
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: 7 mm | February: 7 mm | March: dry | April: 7 mm | May: 7 mm | June: 7 mm | July: 5 mm + | August: 5 mm + | September: 5 mm + | October: 5 mm + | November: 7 mm | December: 7 mm |
- Nov–Feb7 mm semi-dry
- Mardrysuit
- Apr–Jun7 mm semi-dry
- Jul–Oct5 mm with hood and gloves
Swell through the year
The rough end of each month — nine days in ten come in under it.
Amber is over 2.5 m.
Tides
Tropical storms
No tropical storm has come within 250 km in 30 years of records. Swell and wind set the season, not cyclones.
- 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
Channel Islands marine life — what you'll see diving
| Species | When | Observed window | Reliability | Evidence | Records |
|---|---|---|---|---|---|
| Ocean sunfish | Aug–Oct | Near-guaranteed | 1856 | ||
| Blue shark | Aug–Oct | Near-guaranteed | 1933 | ||
| Sardine | Aug–Oct | Near-guaranteed | 1996 | ||
| Common dolphin | All year | Near-guaranteed | 129 | ||
| Common thresher | Aug–Sep | Near-guaranteed | 1890 | ||
| Humpback whale | All year | Near-guaranteed | 411 | ||
| California sea lion | All year | Near-guaranteed | 206 | ||
| Blue whale | Jun–Jul | Likely | 146 | ||
| Bottlenose dolphin | Jan, Mar–Apr | Likely | 38 | ||
| Harbour seal | Jan–Mar | Likely | 52 | ||
| Grey whale | Jan, Mar | Likely | 33 | ||
| Minke whale | May, Jul | Hit-or-miss | 15 | ||
| Orca | Dec–Feb | Hit-or-miss | 13 |
- 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 Channel Islands — common questions
- When is the best time to dive the Channel Islands?
- Plan for June to October once the water has warmed to 19 °C from 15. The marine life holds steady all year, so the weather picks the month.
- When is the diving season at the Channel Islands?
- The diving season at the Channel Islands runs June to October.
- Is the diving at the Channel Islands good for beginners?
- Not really. It is for experienced divers, so it is not a place to learn or to make your first dives after certification.
- How warm is the water at the Channel Islands?
- Between 14 and 20 °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 at the Channel Islands?
- A drysuit covers the coldest water of the year. In the warmest months a 5 mm with hood and gloves is enough.
- What is the visibility like at the Channel 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 Channel Islands?
- The most consistently recorded species are Ocean sunfish (near-guaranteed), Blue shark (near-guaranteed) and Sardine (near-guaranteed), from 8,721 records within 60 km.
- Does the Channel Islands get tropical storms?
- No. None has passed within 250 km in 30 years of records.
- Is there current at the Channel Islands?
- The tide rises and falls 2.2 m around the full and new moon, against 1.1 m in between. How much of that becomes current depends on the shape of the channel.
- When should I avoid the Channel Islands?
- January–March are the weakest months for conditions.
- How do you dive the Channel Islands?
- Mostly from liveaboards and day boats. Trips run through the season, Jun–Oct.