December Weather in Rio de Mouro PortugalDaily high temperatures decrease by 2°F, from 60°F to 57°F, rarely falling below 52°F or exceeding 64°F. Daily low temperatures decrease by 2°F, from 51°F to 48°F, rarely falling below 42°F or exceeding 57°F. For reference, on July 28, the hottest day of the year, temperatures in Rio de Mouro typically range from 65°F to 79°F, while on January 18, the coldest day of the year, they range from 48°F to 57°F. The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on December. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day. La Paloma, Uruguay (5,834 miles away) and Ardrossan, Australia (10,617 miles) are the far-away foreign places with temperatures most similar to Rio de Mouro (view comparison). CloudsThe month of December in Rio de Mouro experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 49% throughout the month. The highest chance of overcast or mostly cloudy conditions is 51% on December 13. The clearest day of the month is December 1, with clear, mostly clear, or partly cloudy conditions 52% of the time. For reference, on December 13, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 51%, while on July 19, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 91%. PrecipitationA wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Rio de Mouro, the chance of a wet day over the course of December is essentially constant, remaining around 28% throughout. For reference, the year's highest daily chance of a wet day is 30% on November 22, and its lowest chance is 1% on July 30. RainfallTo show variation within the month and not just the monthly total, we show the rainfall accumulated over a sliding 31-day period centered around each day. The average sliding 31-day rainfall during December in Rio de Mouro is essentially constant, remaining about 3.0 inches throughout, and rarely exceeding 8.2 inches or falling below 0.2 inches. SunOver the course of December in Rio de Mouro, the length of the day is essentially constant. The shortest day of the month is December 21, with 9 hours, 27 minutes of daylight and the longest day is December 1, with 9 hours, 39 minutes of daylight. The earliest sunrise of the month in Rio de Mouro is 7:36 AM on December 1 and the latest sunrise is 19 minutes later at 7:55 AM on December 31. The earliest sunset is 5:15 PM on December 6 and the latest sunset is 10 minutes later at 5:25 PM on December 31. Daylight saving time is observed in Rio de Mouro during 2024, but it neither starts nor ends during December, so the entire month is in daylight saving time. For reference, on June 20, the longest day of the year, the Sun rises at 6:12 AM and sets 14 hours, 53 minutes later, at 9:05 PM, while on December 21, the shortest day of the year, it rises at 7:52 AM and sets 9 hours, 27 minutes later, at 5:19 PM. The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation. MoonThe figure below presents a compact representation of key lunar data for December 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.
HumidityWe 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 chance that a given day will be muggy in Rio de Mouro is essentially constant during December, remaining around 0% throughout. For reference, on August 28, the muggiest day of the year, there are muggy conditions 16% of the time, while on January 1, the least muggy day of the year, there are muggy conditions 0% of the time. WindThis 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 Rio de Mouro is essentially constant during December, remaining within 0.3 miles per hour of 12.7 miles per hour throughout. For reference, on December 14, the windiest day of the year, the daily average wind speed is 13.0 miles per hour, while on September 16, the calmest day of the year, the daily average wind speed is 10.3 miles per hour. The highest daily average wind speed during December is 13.0 miles per hour on December 15. The wind direction in Rio de Mouro during December is predominantly out of the north from December 1 to December 12 and from December 28 to December 31 and the east from December 12 to December 28. Water TemperatureRio de Mouro 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 surface water temperature in Rio de Mouro is essentially constant during December, remaining within 1°F of 61°F throughout. Growing SeasonDefinitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere). Temperatures in Rio de Mouro are sufficiently warm year round that it is not entirely meaningful to discuss the growing season in these terms. We nevertheless include the chart below as an illustration of the distribution of temperatures experienced throughout the year. Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F. The average accumulated growing degree days in Rio de Mouro are gradually increasing during December, increasing by 140°F, from 4,061°F to 4,201°F, over the course of the month. Solar EnergyThis 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 in Rio de Mouro is essentially constant during December, remaining within 0.1 kWh of 2.1 kWh throughout. The lowest average daily incident shortwave solar energy during December is 2.1 kWh on December 24. TopographyFor the purposes of this report, the geographical coordinates of Rio de Mouro are 38.775 deg latitude, -9.328 deg longitude, and 387 ft elevation. The topography within 2 miles of Rio de Mouro contains only modest variations in elevation, with a maximum elevation change of 476 feet and an average elevation above sea level of 522 feet. Within 10 miles contains only modest variations in elevation (1,693 feet). Within 50 miles contains very significant variations in elevation (2,218 feet). The area within 2 miles of Rio de Mouro is covered by artificial surfaces (66%), cropland (20%), and trees (13%), within 10 miles by artificial surfaces (34%) and cropland (24%), and within 50 miles by water (61%) and cropland (19%). Data SourcesThis report illustrates the typical weather in Rio de Mouro, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016. Temperature and Dew PointThere is only a single weather station, Lisbon Humberto Delgado Airport, in our network suitable to be used as a proxy for the historical temperature and dew point records of Rio de Mouro. At a distance of 17 kilometers from Rio de Mouro, closer than our threshold of 150 kilometers, this station is deemed sufficiently nearby to be relied upon as our primary source for temperature and dew point records. The station records are corrected for the elevation difference between the station and Rio de Mouro according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations. Please note that the station records themselves may additionally have been back-filled using other nearby stations or the MERRA-2 reanalysis. Other DataAll data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , 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 airports and weather stations are provided by AskGeo.com . Maps are © OpenStreetMap contributors. DisclaimerThe information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site. We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands. We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader. Please review our full terms contained on our Terms of Service page. |