LISBON · SEPTEMBER · 38.72° N
September is the month Lisbon’s thermometer steps back without the sky changing sides. IPMA’s 1991-2020 normals for the city give an average high of 80.2°F (26.8°C), an average low of 63.3°F (17.4°C) and 1.41 inches of rain across 3.7 wet days. The hills that punish you in August become walkable again around two in the afternoon.
What the month takes back is light and water. Daylight is down to 12 hours 29 minutes by the 15th, the sun is gone by 7:45 p.m. local time, and the sea off the coast averages 64.7°F. Wait four weeks and October brings 4.05 inches of rain over 8.3 wet days, which is a different trip entirely.
THE MONTH AT A GLANCE · LISBON IN SEPTEMBER
September gives you August’s warmth minus four degrees, dry weather in 27 days out of 30, and a sea at 64.7°F that suits a short swim rather than a beach week.
IPMA NORMALS 1991-2020 · STATION 579 LISBOA GAGO COUTINHO · SEA 2015-2024
Go for: hill walking at midday, miradouro evenings that still end warm, Belém and the Gulbenkian without August’s heat, and rain in single digits of days.
Think twice before: booking September as a swimming holiday. A sea at 64.7°F, measured as a mean of daily maxima, is a twenty-minute proposition for most visitors.
Normals: IPMA station 579 · Sea: Open-Meteo Marine · Fares: Metropolitano de Lisboa and Carris 2026 · full sources at the end
On this page
- Lisbon weather in September80.2°F highs, 63.3°F lows, 3.7 rain days
- Sea temperature for swimming64.7°F, and why that figure runs warm
- Crowds, prices and the tourist taxWhat is fixed at €1.90 and what we could not source
- Things to do, with tickets and hoursJerónimos €18, Gulbenkian €16, Oceanário €25 after 4 p.m.
- A two-day itineraryTwo days between 7:17 a.m. and 7:45 p.m.
- September vs August and October84.2°F, 80.2°F and 72.7°F, with the rain columns
- Is September a good time to visit?Yes for walkers, no for a beach week
Everything below is dated to the month. Where you sleep, how you reach the city from the US and what the whole country costs belong elsewhere: the flights guide, the where-to-stay guide and the trip-cost breakdown carry those.
Lisbon weather in September: average highs, lows and rain days
| Measure | September in Lisbon |
|---|---|
| Average high | 80.2°F (26.8°C) |
| Average low | 63.3°F (17.4°C) |
| Precipitation | 1.41 in |
| Days with 0.04 in (1 mm) or more | 3.7 |
| Days with 0.39 in (10 mm) or more | 1.3 |
| Daylight on Sept 15 | 12h 29m |
| Sunrise / sunset, Sept 15 | 7:17 a.m. / 7:45 p.m. local |
| Sea surface (mean of daily maxima) | 64.7°F (18.2°C) |
Every figure here comes from IPMA, Portugal’s national weather service, and specifically from its 1991-2020 climatological normals for station 579, Lisboa Gago Coutinho, at 103.9 meters of altitude. That provenance is worth a sentence: it is a real thermometer inside the city, not a reanalysis grid cell smeared across thirty miles of coastline. The month reads 80.2°F by day, 63.3°F at night, 1.41 inches of rain in total.
Wet days are the number that decides a trip, and September carries 3.7 of them at 1 mm (0.04 inch) or more, with 1.3 reaching 10 mm (0.39 inch). Those are IPMA’s thresholds, not the 0.10-inch cutoff American climate tables use, so the counts are not interchangeable with a US city’s. Arithmetic on the two figures says roughly a third of the month’s wet days are the heavy kind, and the rest barely interrupt a walk.
The day-to-night spread runs close to 17°F. A tiled lane at 80°F in the afternoon and a miradouro at 63°F after dark are two different climates, and the second one comes with river air. One light layer in the daypack settles it, plus shoes with grip for the cobbles, which the packing guide details at length.
Light is the quiet loss. On September 15 the city gets 12 hours 29 minutes of it: sunrise and sunset are published at 06:17 and 18:45 UTC, and Lisbon runs an hour ahead in September, so locally that is 7:17 a.m. and 7:45 p.m. Plan the last monument for the afternoon and the viewpoint for 7 p.m., because by mid-month the golden hour and dinner collide.
Can you swim in Lisbon in September? Sea temperature and what it feels like
The water off Lisbon averages 64.7°F (18.2°C) in September in the Open-Meteo Marine record for 2015-2024. One nuance travels with that number: it is the mean of daily maxima, the warmest reading of each day, so it sits a shade above what a full 24-hour average would show. Treat 64.7°F as the optimistic end of the range, not the middle of it.
In practice, mid-60s Atlantic water is a short-swim temperature. Ten minutes is invigorating, twenty is a decision, an hour wants a wetsuit. Families with small children tend to last about as long as the first shriek. The beach towns within reach of the city are covered in Cascais and Ericeira, where the surf schools rent neoprene by the half day.
On wind and swell we have nothing sourced: our marine data carries temperature and nothing else, so no September surf or chop claim appears here. One official hint of exposure does exist. Belém Tower states that it can close whenever visitor safety is compromised by weather, which tells you the riverfront takes real gusts. Nazaré is where the Atlantic’s autumn energy becomes visible.
How busy is Lisbon in September? Crowds, prices and the demand peak
Two kinds of price shape a September trip. The tariffed ones do not move with the season at all: a Carris/Metro single is €1.90 loaded on a navegante occasional card, the 24-hour ticket €7.25, the Jerónimos cloister €18. The demand-driven one is your room, and we could not source a verified month-by-month rate curve for Lisbon, so no such curve is printed. The country-level shape sits in the 12-month verdict.
Where September pressure is documented is at the monument door. Jerónimos states plainly that tickets should be bought online because they frequently sell out and cannot then be bought on the day of the visit. Buy yours when you fix the dates, and note the cloister is closed on Mondays. The site also provides no audio guides and no audio systems, so read up before you go in.
Lisbon adds a municipal tourist tax per night on top of the room rate. We tried to read the amount at the source and could not: the city’s own information portal refuses automated reading and the Diário da República requires JavaScript. So no figure is served here rather than a plausible one. Ask the property to state the per-night amount in writing at booking, and count it per person per night in your budget.
The one upgrade that changes the month is the ticket in your pocket. The plain 24-hour Carris/Metro pass is €7.25; the version that adds the CP suburban trains, the ones to Sintra and Cascais, is €11.40. That €4.15 difference buys the escape hatch for the day the city feels crowded, and the ferry variant sits between them at €10.35.
Things to do in Lisbon in September
Four degrees change the shape of a day. At 80.2°F rather than August’s 84.2°F, the climb from Baixa to the castle is a walk instead of an ordeal, and the 1.41 inches of rain against October’s 4.05 keeps outdoor tables and viewpoint evenings a safe bet. With 12 hours 29 minutes of daylight, a Belém morning and a miradouro sunset still fit inside one day without rushing lunch.
The fixed points, with their numbers. Jerónimos cloister: €18, Tuesday to Sunday 09:30 to 17:30, last entry 17:00; the church keeps its own hours, 10:30 to 17:00 Tuesday to Saturday and 14:00 to 17:00 on Sundays. Belém Tower: €15. Gulbenkian: €18 all inclusive, €16 for Museum plus CAM, €8 for temporary shows, open Wednesday to Monday 10:00 to 18:00, closed Tuesdays. Oceanário: 10:00 to 20:00, last entry 19:00.
Free is narrower than the internet suggests. The Acesso 52 waiver at Jerónimos and Belém Tower applies to Portuguese nationals and residents in Portugal, any day of the year, so an American visitor pays €18 and €15 whatever the calendar says, and the widely repeated free Sunday morning is not a thing. The Gulbenkian’s two windows are similar: Sunday from 14:00 for under-18s and specific cardholders, Saturday 18:00 to 21:00 for under-30s with the free Cartão Gulbenkian. The miradouros and the riverfront cost nothing, always.
Lisbon in September: two-day itinerary and sunset times
Day one, west along the river. Out by 8:30 with the city still cool, and at the Jerónimos gate for the 09:30 opening with an online ticket in hand (€18). Belém Tower at 11:30 (€15, and it can shut in bad weather). Lunch late, then hand the hottest stretch of the afternoon to the Gulbenkian, open until 18:00 and shut on Tuesdays, €16 for the museum and the CAM together. Be at a viewpoint by 19:00: the sun sets at 7:45 p.m.
Day two, uphill then indoors. Alfama on foot from 8:00, because tram 28 costs €3.30 paid to the driver against €1.90 on a navegante card, and the card itself is €0.50 at any metro machine. Afternoon at the Oceanário, where the 16:00 to 18:30 slot is €25 rather than €29 at opening, 5 percent less online, and a visit runs 90 minutes to two hours. If one of the month’s 3.7 wet days lands on you, that aquarium slot and the Gulbenkian absorb an entire afternoon.
Lisbon in September vs August and October
| Measure | August | September | October |
|---|---|---|---|
| Average high | 84.2°F (29.0°C) | 80.2°F (26.8°C) | 72.7°F (22.6°C) |
| Average low | 65.3°F (18.5°C) | 63.3°F (17.4°C) | 58.8°F (14.9°C) |
| Precipitation | 0.20 in | 1.41 in | 4.05 in |
| Days ≥ 0.04 in (1 mm) | 1.0 | 3.7 | 8.3 |
| Sea (mean of daily maxima) | 66.2°F (19.0°C) | 64.7°F (18.2°C) | 66.3°F (19.1°C) |
Read the rain column first: 0.20 inches in August, 1.41 in September, 4.05 in October, with wet days going 1.0, 3.7, 8.3. Temperature slides gently, four degrees from August and eleven and a half between September and October. The sea barely budges across the three, and September is in fact the coolest of them by about a degree and a half, a reminder that the marine series covers 2015-2024 while the land normals cover 1991-2020.
Shifting four weeks either way is a straight trade. Back into August and you buy near-guaranteed dry days and warmer nights, paying with midday heat on hills that offer no shade. Forward into October and you gain comfortable walking temperatures and lose more than four inches of rain to plan around, on a day that ends earlier every week.
Is September a good time to visit Lisbon?
Yes, if your trip is made of streets, viewpoints, museums and long dinners. Warm afternoons, 3.7 wet days out of 30 and evenings that stay pleasant at 63°F make this the best walking month of the Lisbon calendar. No, if the point is the water. A sea at 64.7°F, measured generously, will not carry a family beach week, and no amount of sunshine changes that.
If swimming is the reason for the trip, take August: 84.2°F highs, 0.20 inches of rain and a sea at 66.2°F, with the heat as the bill. If cool air and thin crowds matter more than dry ones, October’s 72.7°F days are lovely between showers, and the 8.3 wet days want a plan B. Neither month gives you both at once.
What no other month offers is the pairing: summer warmth at 80.2°F with only 1.41 inches of rain and still more than twelve hours of daylight to spend on it.
The last word
Book the Jerónimos slot the day you book the flight, then let September do the rest: it is the one month that lets you climb Lisbon at two in the afternoon and still be warm at a viewpoint at eight. One small thing to get right on arrival. The €1.90 ticket covers a single journey for one hour after validation, and it will not let you into the metro twice in a row, so load a few euros of zapping onto the same €0.50 card and stop counting.
Sources & data for this guide
- September normals (80.2°F high, 63.3°F low, 1.41 in) and wet-day counts (3.7 at 1 mm, 1.3 at 10 mm) · IPMA climatological normals 1991-2020, station 579 Lisboa Gago Coutinho, altitude 103.9 m · checked Sep 10, 2026
- August and October normals, same station and same period · IPMA · checked Sep 10, 2026
- Sea surface 64.7°F, mean of daily maxima 2015-2024 · Open-Meteo Marine API · checked Sep 10, 2026
- Daylight 12h 29m; sunrise 06:17 UTC and sunset 18:45 UTC on Sept 15, converted to Europe/Lisbon · sunrise-sunset.org · checked Sep 10, 2026
- Fares: €1.90 single on navegante, €0.50 card, €7.25 / €10.35 / €11.40 24-hour tickets · Metropolitano de Lisboa, Tarifas 2026 (PDF), in force Jan 1, 2026 · checked Sep 10, 2026
- On-board fares: €2.30 bus, €3.30 tram (28 included), €4.30 funicular, €6.20 Santa Justa lift · Carris, Novo Tarifário 2026 · checked Sep 10, 2026
- Jerónimos: €18 cloister, hours, Monday closure, sell-out warning, no audio guides, Acesso 52 eligibility · Mosteiro dos Jerónimos official site, Visitar · checked Sep 10, 2026
- Belém Tower €15 and weather closures · Torre de Belém official site, Visitar · checked Sep 10, 2026
- Oceanário slot prices (€29 / €27 / €25 adult) and hours · Oceanário de Lisboa official ticket page · checked Sep 10, 2026
- Gulbenkian prices, hours and the two free windows · Fundação Calouste Gulbenkian official pages · checked Sep 10, 2026
- Municipal tourist tax: amount deliberately not served. informacoeseservicos.lisboa.pt returns 403 to automated reading and diariodarepublica.pt requires JavaScript · attempted Sept 8, 2026
- No September festival or event is named because our primary sources carry no dated one for the month · hours and fares change, confirm with each operator when you book.