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Research · Weather

Porto Weather by Month (2026 Data)

The official IPMA normals for Porto, month by month: temperature, rain, sunshine, sea, wind and fog - all verified, all in one planner.

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  • 11 min read

Key findings

  1. 15.3 °CPorto averages 15.3 °C (59.5 °F) a year, from 10.2 °C in January to 20.2 °C in August.
  2. 105.4 daysPorto logs 105.4 days of rain a year and 1,146.9 mm, most of it November to March.
  3. 2,468 hoursPorto records 2,468 hours of sunshine per year, peaking at 308 hours in July.
  4. 38.6 °CThe hottest day in Porto's weather record is 38.6 °C, set at Pedras Rubras on 7 August 2016.
  5. +0.9 °CPorto's mean annual temperature moved by +0.9 °C between the 1971-2000 and 1991-2020 climate normals.
  6. 18.3 °CThe Atlantic off Porto peaks at 18.3 °C in September, the year's best sea temperature.
  7. 66 daysFog reaches Porto's weather station on 66 days a year, most often in August and September.

Porto sits at 41 degrees north - the same latitude as Rome - yet the official climate record reads nothing like the Mediterranean. The authoritative source is the Normal Climatologica that the national weather service IPMA publishes for the city's station at Pedras Rubras: over 1991-2020 Porto averaged 15.3 °C a year, collected 1,146.9 mm of rain and logged 105.4 rainy days1. That is nearly double London's rainfall in a year - and roughly 47% more sunshine (2,468 hours against London's 1,675)23. The Atlantic that cools the sea also squeezes the clouds dry against the northern coast; latitude alone would never predict this combination. This page walks the year month by month in official numbers: temperature, rain, sunshine, sea, wind and fog. Three findings surprise almost everyone. First, Porto's climate has shifted visibly between the last two official normals - the annual mean rose 0.9 °C and frost nearly disappeared415. Second, August, the warmest month, is also the foggiest at the weather station, with the famous morning haze burning off by noon51.

Porto Portugal weather by month: the year at a glance

Everything a trip or a move hinges on sits in one table. Read the temperature columns as a sandwich of three numbers - the afternoon high, the day's mean, the night's low - then rain, rainy days, sunshine and the sea beside them. The headline: Porto's mean annual temperature is 15.3 °C (59.5 °F), August peaks at 20.2 °C (68.4 °F) and January bottoms at 10.2 °C (50.4 °F)1.

Porto temperature by month

The Porto average temperature by month traces one smooth ocean-damped curve with no winter shock and no summer spike1. October outranks April by 2.7 °C (16.8 vs 14.1) because the Atlantic stores summer heat and releases it into autumn1.

The table's Fahrenheit columns answer the other half of the search: 59.5 °F annual mean, 68.4 °F in August, 50.4 °F in January - a year that never demands either heavy coat or tropical linen4seatemperature.org1264. Nights barely play along with heat: only 4.9 tropical nights (20 °C-plus) a year, which is why Porto hotels got by without air-conditioning for generations15.

Hot days by month
Mean days per month reaching temperature thresholds, IPMA normals 1991-2020
Unit: days per month
  • High >= 25 C
  • High >= 30 C
  • High >= 35 C
Source: IPMA Normal Climatologica 1991-2020, station 5451. The 1,146.9 mm annual total makes Porto one of Europe's wetter capitals-of-comparison - Rome manages 752 mm, Barcelona 558 mm in the same 1991-2020 generation of normals3.

Rainy days are the subtler number. The Porto rainy days per year figure is 105.4 - a third of the year sees at least 1 mm fall, but the Porto average rainy days per year hide where the volume sits: only 38.8 days a year produce 10 mm or more, and 6.9 days cross 30 mm1. Porto's rain is concentrated, not drizzly - it has fewer rain days than London (112) yet twice the water34. Practically: pack for real rain from October to March, and leave the umbrella home in July.

Rainfall by month
Mean monthly precipitation in Porto, IPMA normals 1991-2020
Unit: millimetres (mm) of precipitation
  1. 151.0JanJ
  2. 97.8FebF
  3. 101.1MarM
  4. 95.5AprA
  5. 85.6MayM
  6. 33.7JunJ
  7. 16.6JulJ
  8. 29.3AugA
  9. 68.2SepS
  10. 148.9OctO
  11. 165.9NovN
  12. 153.3DecD
Source: IPMA Normal Climatologica 1991-2020, station 5451. Neither month's record even reaches the 40 °C mark anywhere in the year, and every month from May to September has touched at least 33.5 °C while no warmest-night record anywhere in the year passes 26.8 °C1. The warmest night on record is 26.8 °C (20 June 2003), and the coldest afternoon in the whole 30-year window is a 3.3 °C January day in 200915. Snow survives only as trivia: 0.2 snow days a year - one flakes every five years5(labelled)2. May to August alone deliver 1,135 hours, 46% of the annual total421. July is the one month everyone agrees on: 308 hours, 3.1 rainy days, and mornings that start blue.

Records: hottest and coldest ever, by month
Extreme daily values recorded at Porto/Pedras Rubras within the 1991-2020 normals
Unit: degrees Celsius (C)
  • Record daily high
  • Record nightly low
Source: IPMA Normal Climatologica 1991-2020, station 54515. The Porto Portugal climate rainfall by month barely moved (1,147.1 mm to 1,146.9 mm; 106.5 to 105.4 rain days), but the temperature detail did: nights warmed twice as fast as days (+1.2 °C vs +0.5 °C), 30-degree days rose from 10.1 to 13.0 a year, tropical nights doubled-plus from 2.1 to 4.9, and frost collapsed from 4.2 nights a year to 1.4541.

The national anchors agree. Mainland Portugal averaged 16.47 °C in 2025, the fifth-warmest year since 1931, and the long-run rate is about +0.3 °C per decade since the 1970s7. What this page deliberately does not do is project: no yearly temperature series exists for the Porto station itself (the national series is published as chart images, and no third-party city series could be verified), so the honest trend statement is the two-normals shift above - a measurement of the past, not a forecast of 2050.

Two climate normals, one station: 1971-2000 vs 1991-2020
Mean monthly temperature (TT) at Porto/Pedras Rubras in the last two official 30-year normals
Unit: degrees Celsius (C), monthly mean
  • 1971-2000 normal
  • 1991-2020 normal
Source: IM Ficha 1971-2000 and IPMA Normal 1991-2020, station 5455141.

A quick orientation for readers coming from US norms: Porto's summer afternoons (73-77 °F) run cooler than New York's or Boston's, its winter afternoons (57-59 °F) run warmer than the same cities', and no month ever averages above 77 °F - the ocean caps the top of the scale as surely as it lifts the bottom.

The month-by-month planner
The four numbers a trip actually turns on - air, sea, rain, sun (sources as the master table)
Unit: degrees Celsius and Fahrenheit, days, hours (see columns)
1Jan14.0 / 57.214.312.8124Mild but wet; the greenest the region ever looks
2Feb15.0 / 59.013.810.0129Like January with a hint more light; almond blossom inland
3Mar17.0 / 62.613.89.9192First beach walks; rain still a third of the month
4Apr18.1 / 64.614.910.4217Sunny and fresh; the Douro valley at its most photogenic
5May20.3 / 68.516.28.9258Warm days, cool nights; the best hiking window
6Jun22.7 / 72.917.24.9274Dry and bright; the sea still bracing
7Jul24.3 / 73.917.33.1308Peak sun, peak dry; city heat without Sahara spikes
8Aug24.8 / 76.617.93.2295Warmest month; expect morning coastal fog at the shore
9Sep23.5 / 74.318.35.8224The swimmer's month: warmest sea of the year
10Oct20.7 / 69.317.811.1184Golden and calm until the rains return mid-month
11Nov16.8 / 62.216.813.0139The wettest month; museum and cellar weather
12Dec14.7 / 58.515.412.4124Cool, damp, festive; few crowds
Source: Assembled from IPMA 1991-2020, IPMA/NOAA-attributed sunshine and seatemperature.org (see master table)1266. Compare the coasts and the north-south gradient jumps out - Faro's Algarve water is 2.4-3.4 °C warmer in every single month, and even Lisbon's runs about 1 °C above Porto's6.

For swimmers the practical window is June to September (17.2-18.3 °C): cool by Mediterranean standards, exhilarating by Atlantic ones, and the local answer is always "you get used to it by the second minute". Surfers wear wetsuits year-round and are the only people who call February's 13.8 °C refreshing65. The record gust, 133 km/h, belongs to a February storm of 19725. This is why August photographs from the coast show grey mornings while the city centre basks: the fog band is a few hundred metres deep and stops at the first hill. Humidity stays in the 78-86% band all year, 82% on average, highest in October5.

Fog days by month
Mean days with fog at Porto/Pedras Rubras, IM normals 1971-2000 (latest official fog record)
Unit: days per month with fog
  1. 3.0JanJ
  2. 3.6FebF
  3. 2.9MarM
  4. 3.4AprA
  5. 2.8MayM
  6. 3.7JunJ
  7. 6.2JulJ
  8. 9.3AugA
  9. 11.6SepS
  10. 9.7OctO
  11. 5.6NovN
  12. 4.4DecD
Source: IM Ficha Climatologica 1971-2000, station 5455431.

The rain ranking is the shock: Porto, at 1,146.9 mm, is the wettest of the seven cities - ahead of Amsterdam (850), Dublin (772) and Rome (752)13. Yet it has fewer rain days than London, Dublin or Amsterdam: when it rains here, it pours and finishes. Sunshine splits the difference between the two Europes: 2,468 hours put Porto within 21 hours of Barcelona and 256 of Rome, while every northern peer trails by 688-998 hours234.

Monthly mean temperature: Porto vs its west-European peers
Daily mean per month: Porto (IPMA normals 1991-2020) against London, Paris and Amsterdam (national met services via Wikipedia)
Unit: degrees Celsius (C)
  • Porto
  • Paris
  • London
  • Amsterdam
Source: IPMA normals 1991-2020; Wikipedia climate boxes for the peer cities (labelled)13(labelled)23. The northern coastal ribbon is remarkably flat - Viana do Castelo 15.0 °C, Porto 15.3 °C, Aveiro 15.8 °C, all within 0.8 °C - while the interior north (Vila Real 13.8, Viseu 13.9, Braganca 12.9) runs cooler on sharper winters1.

Same country, same latitude, different winters: the map above is the quick version of that geography, and the table beside it the precise one.

Where Porto sits in Portugal's climate
Continental Portugal: annual mean temperature (1991-2020) of each district's IPMA reference station - a related regional dataset, shown because Porto's own station has no regional split
Unit: degrees Celsius (C), annual mean daily temperature
Aveiro: 15.8Beja: 17.1Braga: 14.9Bragança: 12.9Castelo Branco: 16.1Coimbra: 16.2Évora: 16.6Faro: 18.2Guarda: 11.6Leiria: 14.8Lisboa: 17.3Portalegre: 15.9Porto: 15.3Santarém: 17.1Setúbal: 16.7Viana do Castelo: 15Vila Real: 13.8Viseu: 13.9Aveiro15.8Beja17.1Braga14.9Bragança12.9Castelo Branco16.1Coimbra16.2Évora16.6Faro18.2Guarda11.6Leiria14.8Lisboa17.3Portalegre15.9Porto15.3Santarém17.1Setúbal16.7Viana do Castelo15Vila Real13.8Viseu13.9
Source: IPMA Normal Climatologica 1991-2020 station fichas; Porto/Pedras Rubras = 15.3 C126. May and October are the walkers' months: 20.3-20.7 °C highs, 184-258 sun hours, pre-summer and post-summer light1.

November to March is rain management, not avoidance: 8-13 rainy days a month still leave three dry days in four, and 124-139 sunshine hours mean bright mornings between fronts12. Pack a real rain shell, plan the Port cellars and museums for the afternoons, and note that even in December Porto's daily mean (11.1 °C) runs 2.4 °C above Rome's (8.7 °C)13. Two micro-caveats from the records: August beach mornings may start foggy (9.3 fog days that month at the airport) - wait an hour or take the metro inland; and 30 °C heat, while rare (13 days a year), does arrive in short spikes, so a hotel with air-conditioning is a comfort, not a gimmick51.

Conclusions

  1. Porto's climate is Atlantic, not Mediterranean, and the numbers prove it from three directions: the wettest city in its seven-city peer set (1,146.9 mm against Rome's 752), the coolest summer afternoons of the warm group (24.8 °C in August against Rome's 32.7), and a sea that never passes 18.3 °C136.
  2. The year divides at October and April: eight months carry 93% of the rain and the four summer months just 6.9%, so trip-planning is really rain-planning, and the master table's rainy-day column predicts a stay better than the rainfall column does41.
  3. Visitors' instincts about "grey Porto" are about fog, not rain: 66.2 fog days a year cluster in August and September mornings and burn off by noon, while those same months average only 3.2 days of rain51.
  4. For most travellers the honest best month is September: the year's warmest sea (18.3 °C), a 23.5 °C afternoon, 224 sun hours and pre-autumn light - the month where every curve on this page bends in the visitor's favour at once612.

Methodology

  • Normals 1991-2020 (IPMA, hybrid series) for all temperature and precipitation figures
  • Wind, fog, humidity: normals 1971-2000 - the latest official measurement of these elements at this station
  • Sunshine: IPMA/NOAA-attributed series without a stated baseline (labelled ENC on the page)
  • Peer cities: 1991-2020 generation normals as published in each city's standard climate box

Definition. Climate normals are 30-year averages of weather-station measurements as defined by the World Meteorological Organization; the current reference period is 1991-2020. All temperatures are air temperature in the shade at 2 m; precipitation is the 09:00-09:00 UTC accumulation. The Porto record comes from IPMA station 545 (Porto/Pedras Rubras airport, 41.2322 N, 8.6791 W, 67.7 m altitude).

Data sources. ['IPMA Normal Climatologica Porto/Pedras Rubras 1991-2020 (station 545, v1.0, 2024) - temperature, precipitation, thresholds, records (OFFICIAL)', 'IM Ficha Climatologica 1971-2000, same station - previous normals, wind, fog, humidity, old extremes (OFFICIAL)', 'Wikipedia Porto climate box, sunshine row, IPMA/NOAA-attributed (ENC - labelled; the station has no sunshine recorder)', 'seatemperature.org Porto/Lisbon/Faro monthly sea temperature (AGGREGATOR - labelled; IPMA publishes no monthly SST normals)', 'Wikipedia climate boxes for London, Dublin, Amsterdam, Paris, Barcelona, Rome (ENC - values attributed to the respective national met services)', 'APA/IPMA national climate series 1941-2025 - mainland annual mean and warming rate (OFFICIAL)']

Calculations. ['Fahrenheit: F = C x 9/5 + 32, rounded to 0.1', 'Season precipitation shares: sum of the 1991-2020 monthly normals per season, share of the 1,146.9 mm annual total (script work/data/prepare_data.py)', 'Peer annual means and totals: computed as the sum/mean of the 12 monthly values in each climate box', 'Sunshine per day (6.8 h) and the 150-170 sunny-days band: our arithmetic on the cited series, labelled as estimates on the page', 'March fog (2.9) and thunderstorm (2.0) values: derived as the printed annual minus the other 11 months (PDF layout collision), noted in step2-values.md']

Limitations. ['Station normals describe the airport site 8 km inland; the seafront runs milder nights and foggier summer mornings', "The 1991-2020 ficha is marked 'serie hibrida' (hybrid series) by IPMA", 'Wind/fog/humidity normals are 1971-2000 - older than the temperature baseline, and stated as such wherever quoted', 'Porto sunshine rests on an attributed encyclopedia series, not a station measurement (no sunshine recorder exists there)', 'No yearly Porto temperature series could be verified, so the page shows the two-normals shift and national anchors instead of a projection']

Sources

  1. IPMA - Instituto Portugues do Mar e da Atmosfera, I.P.. “Normal Climatologica - Porto / Pedras Rubras 1991-2020 (station 545, v1.0).” IPMA, 2024. ipma.pt. Accessed 2026-09-16. Back to text
  2. Wikipedia contributors (values attributed to IPMA and NOAA). “Porto - climate box, mean monthly sunshine hours.” Wikipedia, 2026. en.wikipedia.org. Accessed 2026-09-16. Back to text
  3. Wikipedia contributors (values attributed to the Met Office, Met Eireann, KNMI, Meteo-France, AEMET and the Italian Air Force met service). “Climate boxes: London, Dublin, Amsterdam, Paris, Barcelona, Rome.” Wikipedia, 2026. en.wikipedia.org. Accessed 2026-09-16. Back to text
  4. Porto.tours research. “Our calculations from the sources above: Fahrenheit conversions, season shares, peer-city annual totals.” Porto.tours, 2026. porto.tours. Accessed 2026-09-16. Back to text
  5. Instituto de Meteorologia, I.P. (IM, now IPMA). “Ficha Climatologica 1971-2000 - Porto / Pedras Rubras (station 545).” Instituto de Meteorologia, 2001. ipma.pt. Accessed 2026-09-16. Back to text
  6. World Sea Temperature (seatemperature.org). “Porto / Lisbon / Faro average sea temperature, monthly averages.” seatemperature.org (satellite and buoy observations; NOAA, Copernicus Marine), 2026. seatemperature.org. Accessed 2026-09-16. Back to text
  7. APA (Agencia Portuguesa do Ambiente) with IPMA. “Estado do Ambiente / climate series 1941-2025: mainland annual mean and anomalies.” APA / IPMA, 2025. rna2100.apambiente.pt. Accessed 2026-09-16. Back to text

About the author

Tiago Santos
Tiago Santos
Travel Advisor & Porto City Guide Author

Tiago Santos is a born-and-bred Tripeiro with nearly a decade chronicling Porto's shifting culinary and cultural landscape - from back-alley petisqueiras to contemporary architecture. A former contributor to Publico's Fugas supplement and Revista Visao, for this guide he turns official statistics and street-level knowledge into research visitors can check and cite.

Mariana Gomes
Reviewed by
Mariana Gomes
Editor-in-Chief, Porto Tours

Every figure on this page links to its source. How we research

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