Portugal
Best Time to Dive in Sesimbra / Berlengas
39.41°N 9.51°W
The best conditions run May to September for the long days — 13.9 hours of light against 10.7. The marine life holds steady all year, so the weather picks the month.
- Best time
- May–Sep
- Water
- 15–19 °C
- Visibility
- 5–20 m
- Dived from
- day boat
- Tidal range
- 1.4–3.0 m
- Species logged
- 4
Worth knowing: 82% of days see seas over 1.5 m.
Where it is
111 km across · coastline from Natural Earth 10m
Diving in Sesimbra / Berlengas — 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 | Good | Excellent | Excellent | Excellent | Good | Moderate | Poor | Poor |
| Water temp (°C) | 15 | 15 | 15 | 15 | 17 | 18 | 19 | 19 | 19 | 18 | 17 | 16 |
| Visibility (m) | 10–20 | 5–15 | 5–15 | 10–20 | 10–20 | 10–20 | 10–20 | 10–20 | 10–20 | 10–20 | 10–20 | 10–20 |
| Marine life | Peak | Peak | Peak | Peak | Peak | Peak | Peak | Peak | Peak | Peak | Peak | Peak |
| 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 Sesimbra / Berlengas diving season
May to September · Peak season
5 monthsJFMAMJJASOND
- Water temperature
- 17–19 °C
- Visibility
- 10–20 m
- Rain
- 3 days a month
Diving conditionsIt rains less.
Marine lifeOcean sunfish (near-guaranteed) peaks at Sesimbra / Berlengas in these months.
October · Shoulder season
1 monthJFMAMJJASOND
- Water temperature
- 18–18 °C
- Visibility
- 10–20 m
- Rain
- 9 days a month
Diving conditionsIt rains more.
Marine lifeOcean sunfish (near-guaranteed) peaks at Sesimbra / Berlengas in these months.
November to April · Off season
6 monthsJFMAMJJASOND
- Water temperature
- 15–17 °C
- Visibility
- 10–20 m
- Rain
- 10 days a month
Diving conditionsIt rains more. The wind is up.
Marine lifeOcean sunfish (near-guaranteed) peaks at Sesimbra / Berlengas in these months.
- Spring tides run 3.0 m against 1.4 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.
Sesimbra / Berlengas water temperature and weather
569 underwater observation records · 23 surveyed years of ocean data · 10 years of sea temperature
Water & weather
Sesimbra / Berlengas 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
25
rough days a month
Seas top 1.5 m on 82% of days. Enough to cancel a day boat
6
blowy days a month
Gusts over 40 km/h, about where a day boat stays in port
7
wet days a month
2 of them bring heavy rain
| Month | Swell | Gusts over 40 km/h | Wet days | Heavy rain | Air | Daylight |
|---|---|---|---|---|---|---|
| January | 4.7 m | 34% | 10 | 2 | 15 °C | 9.5 h |
| February | 4.8 m | 27% | 9 | 1 | 15 °C | 10.5 h |
| March | 5.6 m | 30% | 10 | 2 | 15 °C | 11.7 h |
| April | 3.6 m | 21% | 10 | 2 | 16 °C | 13.0 h |
| May | 2.7 m | 12% | 4 | 1 | 17 °C | 14.2 h |
| June | 2.8 m | 12% | 4 | 0 | 18 °C | 14.8 h |
| July | 2.5 m | 7% | 1 | 0 | 19 °C | 14.5 h |
| August | 2.9 m | 6% | 1 | 0 | 20 °C | 13.6 h |
| September | 3.2 m | 11% | 4 | 1 | 20 °C | 12.2 h |
| October | 4.3 m | 16% | 9 | 3 | 19 °C | 10.9 h |
| November | 4.5 m | 26% | 11 | 3 | 17 °C | 9.8 h |
| December | 5.1 m | 28% | 10 | 3 | 16 °C | 9.2 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: Moderate | June week 1: Excellent | July week 1: Good | August week 1: Excellent | September week 1: Excellent | October week 1: Good | November week 1: Poor | December week 1: Poor |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Week 2 | January week 2: Poor | February week 2: Poor | March week 2: Poor | April week 2: Poor | May week 2: Moderate | June week 2: Excellent | July week 2: Excellent | August week 2: Excellent | September week 2: Good | October week 2: Good | November week 2: Poor | December week 2: Poor |
| Week 3 | January week 3: Poor | February week 3: Poor | March week 3: Poor | April week 3: Poor | May week 3: Good | June week 3: Excellent | July week 3: Excellent | August week 3: Excellent | September week 3: Good | October week 3: Poor | 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: Excellent | June week 4: Good | July week 4: Excellent | August week 4: Good | September week 4: Good | October week 4: Poor | November week 4: Poor | December week 4: Moderate |
Excellent Good Moderate PoorBest week to go: third of July
January, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 16 °C | 4.4 m | 29 km/h | 31% |
| Week 2 | Poor | 15 °C | 4.7 m | 32 km/h | 31% |
| Week 3 | Poor | 15 °C | 5.0 m | 33 km/h | 29% |
| Week 4 | Poor | 15 °C | 5.0 m | 33 km/h | 26% |
February, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 15 °C | 4.6 m | 32 km/h | 31% |
| Week 2 | Poor | 15 °C | 4.3 m | 32 km/h | 35% |
| Week 3 | Poor | 15 °C | 5.1 m | 31 km/h | 33% |
| Week 4 | Poor | 15 °C | 5.6 m | 31 km/h | 33% |
March, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 14 °C | 5.8 m | 34 km/h | 43% |
| Week 2 | Poor | 14 °C | 5.7 m | 35 km/h | 35% |
| Week 3 | Poor | 15 °C | 5.0 m | 33 km/h | 26% |
| Week 4 | Poor | 15 °C | 4.7 m | 32 km/h | 28% |
April, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 15 °C | 3.7 m | 31 km/h | 33% |
| Week 2 | Poor | 15 °C | 3.6 m | 30 km/h | 38% |
| Week 3 | Poor | 16 °C | 3.8 m | 29 km/h | 32% |
| Week 4 | Moderate | 16 °C | 3.5 m | 30 km/h | 22% |
May, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Moderate | 16 °C | 2.7 m | 31 km/h | 20% |
| Week 2 | Moderate | 16 °C | 3.0 m | 31 km/h | 19% |
| Week 3 | Good | 17 °C | 2.9 m | 32 km/h | 9% |
| Week 4 | Excellent | 17 °C | 2.6 m | 30 km/h | 6% |
June, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 17 °C | 2.7 m | 30 km/h | 10% |
| Week 2 | Excellent | 18 °C | 2.7 m | 30 km/h | 13% |
| Week 3 | Excellent | 18 °C | 2.6 m | 29 km/h | 15% |
| Week 4 | Good | 18 °C | 3.1 m | 30 km/h | 12% |
July, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Good | 18 °C | 3.1 m | 30 km/h | 6% |
| Week 2 | Excellent | 18 °C | 2.5 m | 28 km/h | 3% |
| Week 3 | Excellent | 19 °C | 2.3 m | 29 km/h | 2% |
| Week 4 | Excellent | 19 °C | 2.4 m | 29 km/h | 2% |
August, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 19 °C | 2.5 m | 29 km/h | 2% |
| Week 2 | Excellent | 19 °C | 2.6 m | 28 km/h | 1% |
| Week 3 | Excellent | 19 °C | 2.8 m | 27 km/h | 2% |
| Week 4 | Good | 19 °C | 3.2 m | 27 km/h | 5% |
September, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Excellent | 19 °C | 3.3 m | 27 km/h | 8% |
| Week 2 | Good | 19 °C | 3.1 m | 27 km/h | 13% |
| Week 3 | Good | 19 °C | 3.1 m | 26 km/h | 16% |
| Week 4 | Good | 19 °C | 3.1 m | 26 km/h | 11% |
October, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Good | 18 °C | 3.2 m | 26 km/h | 10% |
| Week 2 | Good | 18 °C | 3.6 m | 27 km/h | 23% |
| Week 3 | Poor | 18 °C | 4.6 m | 29 km/h | 38% |
| Week 4 | Poor | 18 °C | 4.8 m | 30 km/h | 42% |
November, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 18 °C | 5.0 m | 34 km/h | 44% |
| Week 2 | Poor | 17 °C | 4.7 m | 33 km/h | 37% |
| Week 3 | Poor | 17 °C | 4.3 m | 32 km/h | 33% |
| Week 4 | Poor | 17 °C | 4.3 m | 33 km/h | 36% |
December, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 16 °C | 4.9 m | 33 km/h | 34% |
| Week 2 | Poor | 16 °C | 5.1 m | 34 km/h | 39% |
| Week 3 | Poor | 16 °C | 5.1 m | 34 km/h | 38% |
| Week 4 | Moderate | 16 °C | 4.3 m | 29 km/h | 29% |
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: 7 mm | 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–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 1.5 m.
Tides
Tropical storms
1 of the last 30 Septembers saw a tropical storm pass within 250 km. September 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
Sesimbra / Berlengas marine life — what you'll see diving
| Species | When | Observed window | Reliability | Evidence | Records |
|---|---|---|---|---|---|
| Common dolphin | All year | Near-guaranteed | 346 | ||
| Bottlenose dolphin | All year | Near-guaranteed | 43 | ||
| Ocean sunfish | All year | Near-guaranteed | 153 | ||
| Orca | Dec–Feb, Sep | Hit-or-miss | 11 |
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 Sesimbra / Berlengas — common questions
- When is the best time to dive Sesimbra / Berlengas?
- The best conditions run May to September for the long days — 13.9 hours of light against 10.7. The marine life holds steady all year, so the weather picks the month.
- When is the diving season in Sesimbra / Berlengas?
- The diving season in Sesimbra / Berlengas runs May to September.
- Is the diving in Sesimbra / Berlengas good for beginners?
- Yes. It suits Open Water divers, so it works for a first trip after certification.
- How warm is the water in Sesimbra / Berlengas?
- Between 15 and 19 °C at the surface across the year, coldest in March and warmest in August. It runs cooler below the thermocline.
- What wetsuit do I need in Sesimbra / Berlengas?
- A 7 mm semi-dry 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 in Sesimbra / Berlengas?
- Roughly 5 to 20 m depending on the month. That is estimated from satellite chlorophyll-a rather than measured in the water.
- What will I see diving Sesimbra / Berlengas?
- The most consistently recorded species are Common dolphin (near-guaranteed), Bottlenose dolphin (near-guaranteed) and Ocean sunfish (near-guaranteed), from 569 records within 60 km.
- Does Sesimbra / Berlengas get tropical storms?
- Yes. Over 30 years of records a storm passed within 250 km in Sep, most often in September at 1 of 30 years.
- Is there current in Sesimbra / Berlengas?
- The tide rises and falls 3.0 m around the full and new moon, against 1.4 m in between. How much of that becomes current depends on the shape of the channel.
- When should I avoid Sesimbra / Berlengas?
- November–March are the weakest months for conditions.
- How do you dive Sesimbra / Berlengas?
- Mostly from day boats. Trips run through the season, May–Sep.