Climate of Porto

Porto and its metropolitan area feature a Mediterranean climate (Köppen: Csb) with mild wet winters and warm dry summers. According to the Troll-Paffen climate classification, Porto has a warm-temperate subtropical climate (Warmgemäßigt-subtropisches Zonenklima),[2] and a subtropical climate according to Siegmund/Frankenberg.[3] Porto is the wettest major city with a Mediterranean climate.

Porto
Climate chart (explanation)
J
F
M
A
M
J
J
A
S
O
N
D
 
 
147
 
 
14
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15
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17
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18
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17
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14
7
Average max. and min. temperatures in °C
Precipitation totals in mm
Source: Instituto de Meteorologia[1]

Classifications
Street in Porto
Porto Climate according to major climate systems
Climatic scheme Initials Description
Köppen system[4] Csb warm-summer Mediterranean climate
Trewartha system[5] Cs Subtropical dry summer
Alisov system[6] N/A Subtropical climate
Strahler system[7] N/A Marine west coast climate
Thornthwaite system[8]
B4 B'2
 Humid Mesothermal
Neef system[9] N/A

Temperature

Normals

Porto has generally moderate temperatures. The average annual high is around 20 °C (68 °F) and average low around 11 °C (52 °F), ranging from a maxima of 14 °C (57 °F) in January to 25–26 °C (77–79 °F) in August, minima is around 5–6 °C (41–43 °F) in January and 15–16 °C (59–61 °F) in July and August. Unlike the central and southern west coast, the northern west coast of Portugal does not have a pronounced upwelling effect (mainly due to its less exposed coast and lack of capes), this means summer highs are generally higher and winter lows are generally lower than those at the same distance from the coast in the centre and southwest of the country, not only that but variations in temperature are not as extreme from coast to interior. In its metropolitan area, January lows can vary between 7 °C (45 °F) at the coast and 3 °C (37 °F) on the mountainous interior, and August highs vary between 24 °C (75 °F) at the coast and 28 °C (82 °F) in the interior near the Douro valley.[10]

Climate data for Porto (Fontainhas), elevation: 93 m or 305 ft, 1981-2010 normals
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Average high °C (°F) 13.8
(56.8)		 15.0
(59.0)		 17.4
(63.3)		 18.1
(64.6)		 20.1
(68.2)		 23.5
(74.3)		 25.3
(77.5)		 25.7
(78.3)		 24.1
(75.4)		 20.7
(69.3)		 17.1
(62.8)		 14.4
(57.9)		 19.6
(67.3)
Daily mean °C (°F) 9.5
(49.1)		 10.4
(50.7)		 12.6
(54.7)		 13.7
(56.7)		 15.9
(60.6)		 19.0
(66.2)		 20.6
(69.1)		 20.8
(69.4)		 19.5
(67.1)		 16.4
(61.5)		 13.0
(55.4)		 10.7
(51.3)		 15.2
(59.4)
Average low °C (°F) 5.2
(41.4)		 5.9
(42.6)		 7.8
(46.0)		 9.1
(48.4)		 11.6
(52.9)		 14.5
(58.1)		 15.9
(60.6)		 15.9
(60.6)		 14.7
(58.5)		 12.2
(54.0)		 8.9
(48.0)		 6.9
(44.4)		 10.7
(51.3)
Source: IPMA[1]

Extremes

Due to its coastal position, temperatures bellow freezing (0 °C (32 °F)) are rare, but not uncommon, and frosts are never severe. Porto is placed in the USDA hardiness zone 10a.[14] The lowest temperature ever recorded in the city was −4.1 °C (24.6 °F) on 11 January 1941.[15]

Climate data for Porto (Fontainhas), elevation: 93 m or 305 ft, 1981-2010
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °C (°F) 23.3
(73.9)		 23.2
(73.8)		 28.5
(83.3)		 30.2
(86.4)		 34.1
(93.4)		 38.7
(101.7)		 40.0
(104.0)		 40.9
(105.6)		 36.9
(98.4)		 32.2
(90.0)		 26.3
(79.3)		 24.8
(76.6)		 40.9
(105.6)
Record low °C (°F) −3.3
(26.1)		 −2.8
(27.0)		 −1.6
(29.1)		 −0.1
(31.8)		 3.3
(37.9)		 5.6
(42.1)		 9.5
(49.1)		 8.0
(46.4)		 5.5
(41.9)		 1.4
(34.5)		 −0.3
(31.5)		 −1.2
(29.8)		 −3.3
(26.1)
Source: IPMA[1]

Precipitation
Because of the high precipitation, winter is generally the greenest time of the year in Porto

Porto has abundant levels of precipitation, especially high for a Mediterranean climate, reason why Strahler included Porto on the marine west coast climate category. Despite averaging above 1,000 mm (39 in) of precipitation a year, July and August are relatively dry with around 15–30 mm (0.59–1.18 in) falling each month. The wettest period is between October and February, mostly between October and December, the wettest month.

Climate data for Porto (Fontainhas), elevation: 93 m or 305 ft, 1981-2010
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Average precipitation mm (inches) 147.1
(5.79)		 110.5
(4.35)		 95.6
(3.76)		 117.6
(4.63)		 89.6
(3.53)		 39.9
(1.57)		 20.4
(0.80)		 32.9
(1.30)		 71.9
(2.83)		 158.3
(6.23)		 172.0
(6.77)		 181.0
(7.13)		 1,237
(48.7)
Source: IPMA[1]

Humidity

The average relative humidity is around 77%. 81% from November to January and 73% in the summer. Summer can be slightly muggy in the hottest days but is generally comfortable, as temperatures rarelly surpass 30 °C (86 °F).[16]

Climate data for Porto (Fontainhas), elevation: 93 m or 305 ft, 1961-1990
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Average relative humidity (%) 81 80 75 74 74 74 73 73 76 80 81 81 77
Source: NOAA[17]

Other phenomena

Sunshine, UV and daylight

Despite its precipitation, the total hours of sunshine are relatively normal for a region of its latitude. Winters, especially December, are dull and summers are sunny.

Climate data for Porto (Fontainhas), elevation: 93 m or 305 ft, 1961-1990
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Mean monthly sunshine hours 124.0 129.0 192.0 217.0 258.0 274.0 308.0 295.0 224.0 184.0 139.0 124.0 2,468
Mean daily daylight hours 9.6 10.7 12.0 13.3 14.5 15.1 14.8 13.8 12.5 11.1 9.9 9.3 12.2
Percent possible sunshine 40 42 52 55 55 61 66 68 63 54 46 44 54
Average ultraviolet index 2 3 4 6 7 8 8 8 6 4 2 1 5
Source 1: NOAA[17]
Source 2: Weather Atlas[18]
Climate data for Porto (Fontainhas), elevation: 93 m or 305 ft, 1987-2007
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Mean monthly sunshine hours 142.4 155.0 199.6 221.9 276.4 277.3 302.1 284.8 230.1 162.0 139.3 118.2 2,509.1
Source: German Meteorological Service[19]

Wind

As a coastal Atlantic city, winds are most predominant in winter. In the summer, nortada winds prevail and can refresh the city in the hottest days. The city centre is sheltered and seldom gets any strong winds.

Average wind speed (km/h) 1971-2000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Porto (Fontainhas)[11] 19.6 19.7 19.2 19.0 18.1 16.9 17.3 16.3 15.2 16.8 18.4 20.0 18.0
Porto São Gens[12] 8.6 8.7 8.8 9.0 8.3 7.7 7.4 6.8 6.5 6.5 6.5 6.9 8.4
Porto Pedras Rubras[13] 15.7 16.3 15.0 15.0 14.9 13.5 12.5 12.2 11.9 13.3 14.2 16.3 14.2

Sea Temperature
Average sea temperature, according to seatemperature.org:[20]
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
14.3 °C (57.7 °F) 13.8 °C (56.8 °F) 13.8 °C (56.8 °F) 14.9 °C (58.8 °F) 16.2 °C (61.2 °F) 17.2 °C (63.0 °F) 17.3 °C (63.1 °F) 17.9 °C (64.2 °F) 18.3 °C (64.9 °F) 17.8 °C (64.0 °F) 16.8 °C (62.2 °F) 15.4 °C (59.7 °F) 16.1 °C (61.0 °F)
Average sea temperature, according to surf-forecast.com:[21]
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
14.5 °C (58.1 °F) 13.5 °C (56.3 °F) 14.0 °C (57.2 °F) 14.5 °C (58.1 °F) 15.5 °C (59.9 °F) 17.5 °C (63.5 °F) 18.5 °C (65.3 °F) 19.0 °C (66.2 °F) 18.5 °C (65.3 °F) 17.5 °C (63.5 °F) 16.0 °C (60.8 °F) 15.5 °C (59.9 °F) 16.2 °C (61.2 °F)

1961-1990 data
Climate data for Porto (Fontainhas), elevation: 100 m or 330 ft, 1961-1990 normals and extremes
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °C (°F) 22.3
(72.1)		 22.7
(72.9)		 26.5
(79.7)		 27.5
(81.5)		 34.7
(94.5)		 38.7
(101.7)		 38.3
(100.9)		 38.2
(100.8)		 36.9
(98.4)		 32.2
(90.0)		 27.7
(81.9)		 24.8
(76.6)		 38.7
(101.7)
Average high °C (°F) 13.5
(56.3)		 14.3
(57.7)		 16.2
(61.2)		 17.5
(63.5)		 19.6
(67.3)		 22.7
(72.9)		 24.7
(76.5)		 25.0
(77.0)		 24.0
(75.2)		 20.9
(69.6)		 16.7
(62.1)		 13.9
(57.0)		 19.1
(66.4)
Daily mean °C (°F) 9.3
(48.7)		 10.1
(50.2)		 11.5
(52.7)		 12.9
(55.2)		 15.1
(59.2)		 18.1
(64.6)		 19.9
(67.8)		 19.8
(67.6)		 19.0
(66.2)		 16.2
(61.2)		 12.3
(54.1)		 9.9
(49.8)		 14.5
(58.1)
Average low °C (°F) 5.1
(41.2)		 5.9
(42.6)		 6.8
(44.2)		 8.3
(46.9)		 10.6
(51.1)		 13.5
(56.3)		 15.0
(59.0)		 14.6
(58.3)		 13.9
(57.0)		 11.4
(52.5)		 7.9
(46.2)		 5.9
(42.6)		 9.9
(49.8)
Record low °C (°F) −3.3
(26.1)		 −3.0
(26.6)		 −1.8
(28.8)		 0.1
(32.2)		 2.6
(36.7)		 5.6
(42.1)		 9.0
(48.2)		 8.0
(46.4)		 5.5
(41.9)		 1.4
(34.5)		 −0.6
(30.9)		 −2.1
(28.2)		 −3.3
(26.1)
Average precipitation mm (inches) 171.0
(6.73)		 169.0
(6.65)		 112.0
(4.41)		 112.0
(4.41)		 89.0
(3.50)		 53.0
(2.09)		 16.0
(0.63)		 22.0
(0.87)		 64.0
(2.52)		 131.0
(5.16)		 152.0
(5.98)		 176.0
(6.93)		 1,267
(49.88)
Average precipitation days (≥ 1.0 mm) 14.0 13.0 11.0 10.0 9.0 6.0 2.0 3.0 6.0 10.0 12.0 12.0 108
Average relative humidity (%) 81.0 80.0 75.0 74.0 74.0 74.0 73.0 73.0 76.0 80.0 81.0 81.0 76.8
Mean monthly sunshine hours 124.0 129.0 192.0 217.0 258.0 274.0 308.0 295.0 224.0 184.0 139.0 124.0 2,468
Source: NOAA[22]

References
  1. "Normais Climatológicas – 1981–2010(provisórias) – Porto" (in Portuguese). Instituto de Meteorologia. Retrieved 19 January 2013.
  2. Climatic map by Istituto Geografico De Agostini, according to Troll-Paffen climate classification Archived October 4, 2012, at the Wayback Machine
  3. Die Klimatypen der Erde - Pädagogische Hochschule in Heidelberg
  4. Peel, M.C.; Finlayson, B.L. "World Map of Köppen-Geiger climate classification". The University of Melbourne. Archived from the original on January 13, 2015. Retrieved 27 June 2020.
  5. "Trewartha maps". kkh.ltrr.arizona.edu. Retrieved 27 June 2020.
  6. Cmapm, Kliimavöötmed svg: Urmasderivative work (2011-06-16), Русский: Климатические пояса Земли по Б. П. Алисову., retrieved 27 June 2020
  7. "World Strahler Climate Map". Retrieved 27 June 2020.
  8. Feddema (2005), Johannes. "A Revised Thornthwaite-Type Global Climate Classification". ResearchGate. Retrieved 28 January 2021.
  9. "Klimaklassifikation". www.spektrum.de (in German). Retrieved 27 June 2020.
  10. "ClimaAlterações Climáticas em Portugal". Portal do Clima, IPMA. Retrieved 28 January 2021.
  11. "Porto Serra do Pilar 1971-2000 normals and extremes" (PDF). IPMA. Retrieved 28 January 2021.
  12. "Porto São Gens 1971-2000 normals and extremes" (PDF). IPMA. Retrieved 28 January 2021.
  13. "Porto Pedras Rubras 1971-2000 normals and extremes" (PDF). IPMA. Retrieved 28 January 2021.
  14. "Hardiness zones of Portugal" (PDF). Repositório Institucional da Universidade de Lisboa. Check pages 60-62.
  15. Extremes Archived 21 June 2017 at the Wayback Machine Instituto Português do Mar e da Atmosfera, IPMA
  16. "Average Weather in Porto Portugal". weatherspark.com. Retrieved 28 January 2021.
  17. "Porto (08546) - WMO Weather Station". National Oceanic and Atmospheric Administration. Retrieved 28 January 2021.
  18. "Porto, Portugal - Monthly weather forecast and climate data". Weather Atlas. Retrieved 28 January 2021.
  19. "Monthly Averages for Porto". DwD.
  20. "Porto Sea Temperature". seatemperature.org. Retrieved 29 January 2021.
  21. "Matosinhos Water Temperature and Wetsuit Guide (Douro and Minho, Portugal)". surf-forecast.com. Retrieved 29 January 2021.
  22. "Porto (08546) - WMO Weather Station". NOAA. Retrieved April 18, 2019.
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