Benagil in September: Weather, Sea Temperature and How It Compares to August and October

BENAGIL · SEPTEMBER · THE ALGARVE

Late-summer light, a small beach at the foot of a cliff road, and boats idling for the cave next door: September keeps the good half of the Algarve summer. The nearest official thermometer, at Faro, puts the month at an average high of 79.5°F (26.4°C) with 0.85 inch of rain, and fewer than two wet days in a normal September.

The trade sits in the water. The marine average off this coast reads 65.4°F in September, below August’s 66.8°F and below October’s 67.3°F. Air is the compensation: 5.1°F cooler than August by day, and 12 hours 27 minutes of daylight on the 15th. For the cave itself, the operators and where to sleep on this stretch of cliff, our Benagil guide holds the logistics.

On this page

• Average highs, lows and rain days79.5°F days, 0.85 in over 1.9 wet days
• Sea temperature for swimming65.4°F, and what that means in the water
• Crowds, prices and bookingWhere September sits, and what we could not price
• Things to do in Benagil in SeptemberThe cave, Praia da Marinha and the cliff path
• A two-day planHour by hour, from 07:13 to 19:40
• September vs August and OctoberHow the three months compare, degree by degree
• Is September a good time to visit?Yes for walkers, arguable for swimmers

Every figure here comes from two named sources and no third. The air normals are IPMA’s 1991-2020 series for station 554 at Faro, a real thermometer 5 meters above the sea and roughly 60 km (37 miles) east, not a model grid cell. Sea temperatures come from the Open-Meteo Marine API, averaged over 2015-2024. Neither one measures the sea state off Benagil, and the sea state is what decides whether a boat gets inside the cave on a given morning.

Benagil weather in September: average highs, lows and rain days

So: 79.5°F (26.4°C) by day, 64.9°F (18.3°C) at night, 0.85 inch of rain over the month, all of it from IPMA’s 1991-2020 normals at Faro. The station stands at 5 meters on the coast. High ground inland runs colder and a great deal wetter than that, and the far end of the Algarve has its own weather, so treat these as coastal readings and nothing wider.

An average September records rain of at least 1 mm (0.04 inch) on 1.9 days, and 0.7 of those days reach 10 mm (0.39 inch). Spread 0.85 inch across 1.9 days and the typical wet day lands under half an inch. Watch the threshold before you compare notes with a US almanac: IPMA counts from 0.04 inch, American tables usually count from 0.10 inch, and the two sets of counts are not interchangeable.

Between the 79.5°F afternoon and the 64.9°F night sits a spread of 14.6°F, and it opens quickly once the sun drops behind the cliffs. A swimsuit dries on the walk back up. Bare shoulders at a ten o’clock dinner table do not work every evening. One long-sleeved layer per person and a spare swimsuit cover the month, and our packing guide handles the rest of the country.

September 15 gives 12 hours 27 minutes of daylight, with sunrise at 07:13 and sunset at 19:40 in local summer time (06:13 and 18:40 UTC). That is room for a boat at eight, a long beach afternoon, and a cliff walk that ends before you need a phone light. Dinner outdoors still starts in daylight.

Can you swim in Benagil in September? Sea temperature and what it feels like

The sea surface off Benagil averages 65.4°F in September, from the Open-Meteo Marine API over 2015-2024. One caveat travels with that number and should not be dropped: it is the mean of daily maxima, a shade warmer than a 24-hour mean. An eight o’clock swim starts below 65.4°F, a four o’clock swim starts above it.

Call it cool-water swimming with a warm exit. The first minute stings, the next ten are comfortable for most adults, and the 79.5°F air closes the 14.1-degree gap about as fast as you can find a towel. An hour of snorkeling is a different proposition and argues for a thin wetsuit, which is worth asking about when you book a boat rather than on the slipway.

On wind and swell we have to hold our hands up: no station on this stretch measures the sea state, and we could not verify September normals for wave height or wind. So we give none. Since the sea state is exactly what decides whether a tour enters the cave or turns around outside it, ask the operator on the morning itself, and keep a spare morning in the plan.

How busy is Benagil in September? Crowds, prices and the demand peak

September is the back end of the Algarve’s summer, and the weather explains most of the demand: 79.5°F days and 1.9 wet days still read as beach weather on any booking site. What we will not do is rank the month on price. We found no monthly occupancy series and no room-rate series for Benagil or its stretch of coast, so we crown no month cheap and no month expensive. Our Portugal trip cost guide gives the national orders of magnitude instead.

Two things deserve to be locked before the flight, and neither is the flight: the car and the bed. Benagil is a hamlet above one cove, with stations and bus links out in the coastal towns, so most visitors drive, and our car guide covers the toll transponder and the insurance trap. We have no booking-window data, so we give no number of weeks. Our where to stay guide and flights guide set the rest of the sequence.

On the lodging tax, we could not verify whether a per-night charge applies here, at what rate, or in which months, so we give no percentage and no euro figure. Budget for one, ask at check-in, and be pleased if nothing appears on the bill.

One upgrade genuinely changes the month: a smaller boat on a fixed early departure rather than the cheapest midday seat. The cave is the same cave either way, the crowd around it is not. No fare for these trips is in our sources, so treat the operators’ own boards at the beach as the price list, and remember that nothing you pay buys a calm sea.

Things to do in Benagil in September: the sea cave, Praia da Marinha and the cliff path

September allows the unplanned swim, and October largely does not. Air of 79.5°F against 73.9°F, 0.85 inch of rain against 2.20, 1.9 wet days against 6.0: you can walk out of the door without checking a forecast and be right nineteen days in twenty. That freedom is the month’s real gift, and it is gone by Halloween.

The Algar de Benagil, the domed sea cave with the hole in its roof, sits along the cliff from the beach and is reached from the water. West and east of it, Praia da Marinha and the coves toward Carvoeiro string together on the clifftop path, and Ponta da Piedade beyond Lagos makes the obvious second boat. We could not verify boat fares, cave-access rules or the size of the parking area above the beach, so none of those numbers appear.

What the calendar moves here is the air, not the water. The sea reads 66.8, 65.4 and 67.3°F across August, September and October, a band of 1.9 degrees. The air moves 10.7°F over the same stretch. So the cliff walk is the thing that changes: in September it is a 79.5°F outing instead of August’s 84.6°F, with the same cool swim waiting at the bottom of the steps.

Plenty of the month costs nothing. Portuguese beaches and the clifftop paths between them carry no ticket, in September as in February, and the viewpoint walk above the cave is the best free hour on this coast. Parking is the exception: we could not verify the charge or the number of spaces above the beach, so assume you will pay and arrive early.

Benagil in September: a two-day itinerary

Day one runs on the light. Sunrise is at 07:13, so coffee at 07:45 and a boat around 08:30 puts you at the cave with the sun low in the opening. Swim from the beach before eleven while the 65.4°F water still feels like a decision rather than a dare, then drive ten minutes to Carvoeiro for a long lunch out of the 79.5°F middle of the day. Back on the clifftop path at five, sunset at 19:40, dinner after.

Day two starts at Praia da Marinha for the walk east, with the afternoon given to Lagos or the coves at Ponta da Piedade. If the weather turns, the odds say it is one of 1.9 days: take the inland option, Faro‘s old town and its market, and keep the boat for the next morning. The same swap works when the water is too rough for the cave, which happens on days the forecast calls sunny.

Benagil in September vs August and October

Air falls in two even steps: 5.1°F from August to September, 5.6°F from September to October, 10.7°F across the pair. Rain does not behave so politely. August is close to bone dry at 0.12 inch and 0.2 wet days, September adds 0.85 inch over 1.9 days, and October jumps to 2.20 inches over 6.0 days, more than three times September’s count. The sea, all three figures from the marine API rather than the station, barely moves: 66.8, 65.4, 67.3°F.

Shift four weeks earlier and you buy heat and dryness, at the cost of August prices and August company on a very small beach. Shift four weeks later and you gain the warmest water of the three months, 67.3°F, plus quieter paths, and you accept a one-in-five chance of rain on any given day and afternoons nearly six degrees cooler for walking. September takes the middle seat and rarely regrets it.

Is September a good time to visit Benagil?

Yes, for anyone whose trip is built on walking, boats and beach afternoons. Days of 79.5°F, under an inch of rain and more than twelve hours of light make a short stay reliable in a way October cannot promise. The people who should hesitate are cold-water skeptics and families who want children splashing for hours: 65.4°F, measured as a daily maximum, is bracing rather than balmy.

If that is you, August is the month to prefer, not October: 84.6°F days, 0.12 inch of rain across the whole month, and a sea at 66.8°F, warmer than September by 1.4 degrees. October answers a different wish, cooler walking and the warmest sea of the three at 67.3°F, and asks 2.20 inches of rain in return. Our best-time guide runs the same argument for the whole country.

No other month puts summer air over an almost-empty rain gauge with a sunset at 19:40: that combination belongs to September alone on this coast.

The last word

Book the car, book the bed, and keep two mornings free for the cave so the sea gets a second chance to cooperate. Then note the smallest number of the month: the September night low of 64.9°F sits within half a degree of the 65.4°F sea. The water is holding roughly the temperature of your coolest hour, which is why it feels colder at eight in the morning than the table suggests. Take a light layer down the steps with the towel.

Sources & data for this guide

• September normals: 79.5°F high, 64.9°F low, 0.85 in, 1.9 days at 0.04 in and 0.7 day at 0.39 in · IPMA, normais climatológicas 1991-2020, station 554 Faro, altitude 5.0 m · checked Sep 23, 2026
• August and October normals (84.6/67.8°F, 0.12 in, 0.2 days · 73.9/60.4°F, 2.20 in, 6.0 days) · same IPMA 1991-2020 series, station 554 Faro · checked Sep 23, 2026
• Sea surface 65.4°F (Sept), 66.8°F (Aug), 67.3°F (Oct), mean of daily maxima 2015-2024 · Open-Meteo Marine API · checked Sep 23, 2026
• Daylight 12h 27m, sunrise 06:13 UTC and sunset 18:40 UTC on September 15, converted to local summer time · sunrise-sunset.org · checked Sep 23, 2026
• Threshold note: IPMA counts rain days from 1 mm (0.04 in) and 10 mm (0.39 in); US tables usually count from 0.10 in, so the counts are not interchangeable.
• Scope note: the Faro station is about 60 km (37 miles) east of Benagil and sits at 5 m; inland high ground is colder and wetter, and no station on this coast measures the sea state.
• We found no occupancy series, no monthly room rates and no lodging-tax rate for the area, so we give no price ranking and no percentage. Boat fares, cave-access rules and parking charges were not verified either · check operators when you book.

To plan your stay

• Best Time to Visit Benagil: Sea Temperature, Rain Days and the Quiet Months
• Benagil in August: Weather, Sea Temperature and Crowds at the Cave
• Benagil in October: Weather, Sea Temperature, Rain Days and Crowds
• Benagil in July: Weather, Sea Temperature, Crowds and What to Do

Nearby places

• Albufeira, Portugal: The Three Zones, the Beaches and the Old Town Hill
• The Algarve: Beaches, Towns and the Two Coasts of Portugal's South
• Carvoeiro, Portugal: the Cove, Algar Seco and the Seven Hanging Valleys Trailhead