LISBON · AUGUST · 38.7° N
August hands Lisbon its warmest daytime normals of the year and almost no rain: an average high of 84.2°F (29°C) and 0.20 inches across the whole month. The hills still climb, the tiles still bounce the glare back at you, and the light holds until half past eight in the evening.
What the month takes away is subtler. The Atlantic off the city averages 66.2°F, which is not the Mediterranean, and the city is deep in its demand peak. If you have not locked the dates yet, the twelve-month view of Portugal makes the wider case; the page you are reading prices August itself.
AUGUST AT A GLANCE · LISBON
August is Lisbon’s hottest, driest and busiest month: superb for long evenings and rooftop hours, mediocre for anyone who came to swim.
AVG HIGH 84.2°F · 0.20 IN OF RAIN · SEA 66.2°F · 13H43 OF DAYLIGHT
Go for: the warmest normals of the Lisbon year, a month that records one rainy day on average, and daylight that runs to 20:32 local time on the 15th.
Think twice before: building the trip around swimming: the sea averages 66.2°F, and that figure is itself a mean of daily maxima, so a morning dip reads colder.
Normals: IPMA station 579, Lisboa Gago Coutinho · Sea: Open-Meteo Marine · Fares: Metropolitano de Lisboa and Carris 2026 · full sources at the end
On this page
- Lisbon weather in AugustHighs of 84.2°F, one rain day, 0.20 in
- Can you swim in Lisbon in August?Sea at 66.2°F, and how that reads
- Crowds, prices and the tourist taxPublished fares, and what we could not verify
- Things to do in Lisbon in AugustJerónimos, Gulbenkian, Oceanário with hours
- Two days in Lisbon in AugustAn hour-by-hour pair of days
- August vs July and SeptemberThree months, five numbers
- Is August a good time to visit Lisbon?Yes for evenings, no for beach weeks
One number sets the tone for everything below: 0.20 inches of rain in an average August, against 1.41 inches in September. Lisbon in August is a city where the weather stops being a variable and the heat, the light and the price of a tram ticket become the planning problem instead.
Lisbon weather in August: average highs, lows and rain days
| Measure | August normal | How it reads on the ground |
|---|---|---|
| Average high | 84.2°F (29°C) | Shade temperature, recorded 103.9 m above sea level |
| Average low | 65.3°F (18.5°C) | Windows open, no jacket at midnight |
| Precipitation | 0.20 in | Close to nothing across 31 days |
| Days with 1 mm or more | 1.0 | One measurably wet day in an average August |
| Days with 10 mm or more | 0.1 | A real downpour roughly one August in ten |
| Daylight, Aug 15 | 13h 43m | Sunrise 06:49, sunset 20:32 local |
Every figure here comes from the same place: the 1991 to 2020 climate normals published by IPMA, Portugal’s national weather service, for station 579, Lisboa Gago Coutinho, sitting at 103.9 m. That matters because it is an instrument in one fixed spot, not a reanalysis grid cell averaged over several miles of city, river and hillside. The station reads 84.2°F for the average August high and 65.3°F for the average low.
Rain barely exists as a category. One day in an average August records at least 1 mm (0.04 inch), and one August in ten sees a day at 10 mm or more. Read the threshold before you compare: IPMA counts from 1 mm, while most US monthly tables count from 0.10 inch, and the two sets of rain-day counts are not interchangeable. What 0.20 inches over a month means in practice is that an umbrella is dead weight.
The daily swing is close to 19°F, from 84.2 down to 65.3. Afternoons on the Alfama slopes are genuinely hot, and by 23:00 on a miradouro the same shirt is thin. Pack for both ends of that gap rather than for the headline: a long-sleeved layer for evenings, shoes that survive polished calçada, and a refillable bottle. The packing guide covers the rest of the country.
Light is the month’s real gift. On August 15 Lisbon gets 13 hours 43 minutes of daylight, with the sun up at 06:49 and down at 20:32 local time (05:49 and 19:32 UTC, converted to Europe/Lisbon summer time). Dinner starts in daylight and the miradouro hour lands after 20:00, which reshapes a day: sightsee early, hide from 14:00 to 17:00, then take back three usable outdoor hours in the evening.
Can you swim in Lisbon in August? Sea temperature and what it feels like
The sea surface off Lisbon averages 66.2°F (19°C) in August, from the Open-Meteo Marine record across 2015 to 2024. Read the small print: that average is built from daily maxima, the warmest reading of each day, so it sits a shade above a true 24-hour mean. The water you meet at nine in the morning is cooler than 66.2°F, not warmer.
In practice that is Atlantic swimming, with an 18-degree gap between the air at 84.2°F and the water. Entry is a shock, twenty minutes is a good session, and children last less than parents expect. It works beautifully as relief from a hot afternoon and poorly as the spine of a beach week. The train line out to Cascais and the surf coast at Ericeira face the same ocean and the same numbers.
On wind and swell we hold no monthly figures for August, so none are served here rather than guessed at. One verified consequence of exposure is worth carrying: Belém Tower states that it can close whenever weather compromises visitor safety, which is the coast reminding you it has moods even in the driest month of the year.
How busy is Lisbon in August? Crowds, prices and the demand peak
August sits squarely in the European summer peak, when school holidays across the continent and the airline schedule point at the same four weeks. We do not hold a month-by-month rate index for Lisbon hotels, so no percentage appears here. What can be quoted are the published prices, and they are steady: a single Carris/Metro ticket on a navegante card costs EUR 1.90, the card itself EUR 0.50, and the 24-hour Carris/Metro ticket EUR 7.25 in August as in February.
Booking behavior is where the peak bites. Jerónimos Monastery says outright that its tickets frequently sell out and then cannot be bought on the day of the visit, which turns a EUR 18 cloister into a closed door for anyone improvising. Treat timed entries and your bed as the two things to fix early, six to eight weeks out (est.), and leave restaurants and day trips loose.
On the municipal tourist tax, we are keeping our cards on the table. Lisbon charges a per-night city tax on top of the room rate, and we could not read the current amount on a primary source: the Câmara Municipal site returns a 403 to automated reading and the Diário da República requires JavaScript. Rather than repeat a figure from a secondary site, no amount is served. Ask the property to state it at booking.
One line item genuinely repays the extra euros in August, and it is transport. The plain 24-hour ticket is EUR 7.25; the version that adds the CP suburban trains, the ones to Sintra and Cascais, is EUR 11.40, and the ferry version is EUR 10.35. Four euros buys the escape from the hot city center. Paying the driver, by contrast, is pure waste: tram 28 costs EUR 3.30 on board against EUR 1.90 from a loaded card.
Things to do in Lisbon in August
What August gives that neither July nor September quite does is a full evening. Sunset at 20:32 and 0.20 inches of rain across the month mean an outdoor plan made at breakfast survives to midnight, which is not true of September and its 3.7 wet days. The month also delivers the year’s warmest average high, 84.2°F, so the sensible shape of a day is early, indoors, then late.
For those indoor hours, the numbers: the Gulbenkian opens Wednesday to Monday, 10:00 to 18:00, closed Tuesdays, EUR 18 all inclusive or EUR 16 for the museum plus the CAM. The Jerónimos cloister runs Tuesday to Sunday, 09:30 to 17:30, last entry 17:00, EUR 18, with no audio guides provided. Belém Tower is EUR 15. The Oceanário opens 10:00 to 20:00, last entry 19:00, and prices by slot: EUR 29 at 10:00, EUR 27 at midday, EUR 25 from 16:00.
Free is narrower than the internet claims. Several guides announce a free Sunday morning at Jerónimos and Belém Tower; the scheme behind that, Acesso 52, applies to Portuguese nationals and residents in Portugal, so an American visitor pays EUR 18 and EUR 15 whatever the day. The Gulbenkian’s real openings: Sundays from 14:00 for under-18s and certain cardholders, and Saturdays 18:00 to 21:00 for under-30s with the Cartão Gulbenkian, which costs nothing to join. Beyond that, the miradouro circuit stays free and works best at 20:00.
Lisbon in August: a two-day itinerary
Day one. Out by 07:30, while the calçada is still cool, for Alfama and the castle slopes. Reach Belém for the 09:30 cloister opening at Jerónimos with a ticket bought online, since it sells out and cannot be bought that day, then Belém Tower at EUR 15 before the glare peaks. Eat long and indoors from 13:00 to 16:00. Take tram 28 with a EUR 1.90 ticket on your EUR 0.50 navegante card, and end on a miradouro for the 20:32 sunset.
Day two. The Gulbenkian at 10:00 when the galleries are cold and empty, EUR 18 for everything, remembering it closes Tuesdays. Afternoon at the Oceanário on the 16:00 to 18:30 slot, EUR 25 for adults, five percent less online, and allow the ninety minutes to two hours the aquarium quotes. If the wind turns and Belém Tower shuts on safety grounds, that afternoon slot absorbs the change. If you would rather chase air, the EUR 11.40 day ticket puts you on the CP train to Cascais.
Lisbon in August vs July and September
| Measure | July | August | September |
|---|---|---|---|
| Average high | 82.9°F | 84.2°F | 80.2°F |
| Average low | 64.4°F | 65.3°F | 63.3°F |
| Precipitation | 0.11 in | 0.20 in | 1.41 in |
| Days with 1 mm+ | 0.4 | 1.0 | 3.7 |
| Sea surface | 66.7°F | 66.2°F | 64.7°F |
Across the three months the air moves less than reputations suggest: 82.9°F in July, 84.2°F in August, 80.2°F in September, all from the same IPMA station and the same 1991 to 2020 period. Rain is where the cliff sits. July logs 0.11 inches and 0.4 wet days, August 0.20 inches and 1.0, September jumps to 1.41 inches and 3.7. The sea peaks in July at 66.7°F, barely above August’s 66.2°F, and drops to 64.7°F by September.
Shift four weeks forward and you trade four degrees of daytime heat for seven times the rainfall and a sea half a degree cooler than useless. Shift four weeks back into July and you keep the dryness and the warmest water of the year, with the same peak-season booking problem. September is the month that buys quieter streets, and it charges for them in wet days.
Is August a good time to visit Lisbon?
Yes, if your Lisbon is a city one: viewpoints, tiles, markets, museums and evenings that stay outdoors until midnight. One rain day in an average month is as close to a guarantee as European weather offers. No, if you pictured beach days, or if 84.2°F on a hill with no shade and a stroller sounds like a fight rather than a holiday.
For the second group, October and May do the same city at gentler numbers, and the year-round comparison lays them out. If the swimming matters more than the dates, the answer is not another month in Lisbon at all, it is the Algarve, where the south-facing coast reads warmer than the 66.2°F Atlantic off the capital.
What August alone offers is 13 hours 43 minutes of daylight paired with 0.20 inches of rain, a combination that no other month on this coast puts on the same page of the record.
The last word
Decide one thing before you book: whether this is a city trip that happens near water, or a beach trip that happens near a city. August answers the first magnificently and the second badly. Then load EUR 10 of zapping onto a navegante card, in one of the fixed amounts the network sells (EUR 3, 5, 10, 15 and up), and let the hills take the 84.2°F afternoon while you sit somewhere with a stone ceiling.
Sources & data for this guide
- August normals: high 84.2°F, low 65.3°F, 0.20 in · IPMA climate normals 1991–2020, station 579 Lisboa Gago Coutinho, altitude 103.9 m · checked Sep 10, 2026
- Rain-day counts at the 1 mm and 10 mm thresholds · IPMA 1991–2020, station 579 · checked Sep 10, 2026 · note: not the 0.10-inch threshold used by most US tables
- July and September normals and sea figures · same IPMA station and period, plus Open-Meteo Marine · checked Sep 10, 2026
- Sea surface 66.2°F, mean of daily maxima 2015–2024 · Open-Meteo Marine API · checked Sep 10, 2026
- Daylight 13h43, sunrise 05:49 UTC and sunset 19:32 UTC on Aug 15 · sunrise-sunset.org, converted to Europe/Lisbon · checked Sep 10, 2026
- Fares EUR 1.90, EUR 0.50 card, EUR 7.25 / 10.35 / 11.40 day tickets, zapping amounts · Metropolitano de Lisboa official 2026 tariff PDF · checked Sep 10, 2026
- On-board fares EUR 2.30 bus, EUR 3.30 tram · Carris Novo Tarifário 2026, in force since Jan 1, 2026 · checked Sep 10, 2026
- Jerónimos EUR 18, hours, Monday closure, sell-outs, no audio guides, Acesso 52 eligibility · mosteirojeronimos.gov.pt, Visitar · checked Sep 10, 2026
- Belém Tower EUR 15 and weather closures · Torre de Belém official site, Visitar · checked Sep 10, 2026
- Oceanário slot prices, 10:00–20:00 hours, last entry 19:00, online discount · Oceanário de Lisboa, Tickets · checked Sep 10, 2026
- Gulbenkian EUR 18 / 16 / 12 / 8, Wed–Mon 10:00–18:00, free windows · Fundação Calouste Gulbenkian, Tickets and Opening hours · checked Sep 10, 2026
- Municipal tourist tax: amount NOT served · informacoeseservicos.lisboa.pt returned 403 and diariodarepublica.pt required JavaScript when checked Sep 10, 2026
- Crowd and demand commentary is editorial: we hold no monthly rate index for Lisbon · prices, hours and closures change, confirm with operators when you book.