Average Weather in Porto Portugal
In Porto, the temperature typically varies from 44°F to 77°F over the course of the year, and is rarely below 35°F or above 88°F.
The warm season lasts for 3.2 months, from June 19 to September 25, with an average daily high temperature above 73°F. The hottest day of the year is July 29, with an average high of 77°F and low of 60°F.
The cool season lasts for 3.5 months, from November 22 to March 7, with an average daily high temperature below 61°F. The coldest day of the year is January 24, with an average low of 44°F and high of 57°F.
Average High and Low Temperature
The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.
Average Hourly Temperature
The length of the day in Porto varies significantly over the course of the year. In 2017, the shortest day is December 21, with 9 hours, 12 minutes of daylight; the longest day is June 21, with 15 hours, 9 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 6:01 AM on June 14, and the latest sunrise is 1 hour, 60 minutes later at 8:00 AM on October 28. The earliest sunset is at 5:05 PM on December 8, and the latest sunset is 4 hours, 6 minutes later at 9:11 PM on June 27.
Daylight saving time (DST) is observed in Porto during 2017, starting in the spring on March 26, lasting 7.1 months, and ending in the fall on October 29.
Sunrise & Sunset with Twilight and Daylight Saving Time
In Porto, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.
The clearer part of the year in Porto begins around June 8 and lasts for 3.2 months, ending around September 14. On July 21, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 85% of the time, and overcast or mostly cloudy 15% of the time.
The cloudier part of the year begins around September 14 and lasts for 8.8 months, ending around June 8. On December 16, the cloudiest day of the year, the sky is overcast or mostly cloudy 57% of the time, and clear, mostly clear, or partly cloudy 43% of the time.
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Porto varies significantly throughout the year.
The wetter season lasts 8.1 months, from September 25 to May 28, with a greater than 22% chance of a given day being a wet day. The chance of a wet day peaks at 38% on October 29.
The drier season lasts 3.9 months, from May 28 to September 25. The smallest chance of a wet day is 5% on July 22.
Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 38% on October 29.
Daily Chance of Precipitation
To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day in the year. Porto experiences very significant seasonal variation in monthly rainfall.
The rainy period of the year lasts for 11 months, from August 6 to July 6, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around December 28, with an average total accumulation of 5.2 inches.
The rainless period of the year lasts for 1.0 months, from July 6 to August 6. The least rain falls around July 20, with and average total accumulation of 0.4 inches.
Average Monthly Rainfall
We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.
The perceived humidity level in Porto, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, staying within 5% of 5% throughout.
Humidity Comfort Levels
This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.
The average hourly wind speed in Porto experiences mildly seasonal variation over the course of the year.
The windier part of the year lasts for 6.4 months, from October 22 to May 2, with average wind speeds of more than 3.7 miles per hour. The windiest day of the year is December 27, with an average hourly wind speed of 4.3 miles per hour.
The calmer time of year lasts for 5.6 months, from May 2 to October 22. The calmest day of the year is September 13, with an average hourly wind speed of 3.1 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Porto varies throughout the year.
The wind is most often from the east for 1.3 months, from January 7 to February 15 and for 1.8 months, from November 5 to December 29, with a peak percentage of 35% on December 17. The wind is most often from the north for 6.0 days, from February 15 to February 21 and for 7.8 months, from February 21 to October 15, with a peak percentage of 54% on July 24. The wind is most often from the south for 3.0 weeks, from October 15 to November 5 and for 1.3 weeks, from December 29 to January 7, with a peak percentage of 32% on January 3.
Porto is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.
The average water temperature experiences some seasonal variation over the course of the year.
The time of year with warmer water lasts for 4.3 months, from June 15 to October 24, with an average temperature above 62°F. The day of the year with the warmest water is August 29, with an average temperature of 64°F.
The time of year with cooler water lasts for 3.5 months, from December 30 to April 15, with an average temperature below 58°F. The day of the year with the coolest water is February 18, with an average temperature of 56°F.
Average Water Temperature
This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.
The average daily incident shortwave solar energy experiences very significant seasonal variation over the course of the year.
The brighter period of the year lasts for 3.1 months, from May 17 to August 21, with an average daily incident shortwave energy per square meter above 6.6 kWh. The brightest day of the year is July 6, with an average of 7.9 kWh.
The darker period of the year lasts for 3.6 months, from October 25 to February 15, with an average daily incident shortwave energy per square meter below 2.9 kWh. The darkest day of the year is December 25, with an average of 1.7 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Porto are 41.150 deg latitude, -8.611 deg longitude, and 272 ft elevation.
The topography within 2 miles of Porto contains significant variations in elevation, with a maximum elevation change of 571 feet, and an average elevation above sea level of 272 feet. Within 10 miles contains very significant variations in elevation (1,247 feet). Within 50 miles contains extreme variations in elevation (4,695 feet).
The area within 2 miles of Porto is covered by artificial surfaces (90%), within 10 miles by artificial surfaces (31%) and water (28%), and within 50 miles by water (41%) and trees (27%).
This report illustrates the typical weather in Porto, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.
Temperature and Dew Point
There are 2 weather stations near enough to contribute to our estimation of the temperature and dew point in Porto.
For each station, the records are corrected for the elevation difference between that station and Porto according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.
The estimated value at Porto is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Porto and a given station.
All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , by Jean Meeus.
All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.
Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.
Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.
Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .
Time zones for aiports and weather stations are provided by AskGeo.com .