September Weather in Valença do Piauí BrazilDaily high temperatures are around 99°F, rarely falling below 96°F or exceeding 103°F. Daily low temperatures increase by 2°F, from 73°F to 75°F, rarely falling below 69°F or exceeding 78°F. For reference, on October 2, the hottest day of the year, temperatures in Valença do Piauí typically range from 75°F to 100°F, while on July 24, the coldest day of the year, they range from 70°F to 95°F. The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on September. 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. Valle San Francisco, Nicaragua (3,330 miles away) is the far-away foreign place with temperatures most similar to Valença do Piauí (view comparison). CloudsThe month of September in Valença do Piauí experiences increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 38% to 49%. The clearest day of the month is September 2, with clear, mostly clear, or partly cloudy conditions 62% of the time. For reference, on March 27, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 80%, while on July 25, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 70%. PrecipitationA wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Valença do Piauí, the chance of a wet day over the course of September is increasing, starting the month at 1% and ending it at 5%. For reference, the year's highest daily chance of a wet day is 61% on March 16, and its lowest chance is 0% on August 14. 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 September in Valença do Piauí is essentially constant, remaining about 0.2 inches throughout, and rarely exceeding 0.8 inches or falling below -0.0 inches. SunOver the course of September in Valença do Piauí, the length of the day is essentially constant. The shortest day of the month is September 1, with 11 hours, 59 minutes of daylight and the longest day is September 30, with 12 hours, 9 minutes of daylight. The latest sunrise of the month in Valença do Piauí is 5:47 AM on September 1 and the earliest sunrise is 15 minutes earlier at 5:32 AM on September 30. The latest sunset is 5:46 PM on September 1 and the earliest sunset is 5 minutes earlier at 5:41 PM on September 30. Daylight saving time is not observed in Valença do Piauí during 2024. For reference, on December 21, the longest day of the year, the Sun rises at 5:30 AM and sets 12 hours, 30 minutes later, at 6:00 PM, while on June 20, the shortest day of the year, it rises at 5:56 AM and sets 11 hours, 45 minutes later, at 5:41 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 September 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 Valença do Piauí is increasing during September, rising from 9% to 16% over the course of the month. For reference, on March 27, the muggiest day of the year, there are muggy conditions 98% of the time, while on August 25, the least muggy day of the year, there are muggy conditions 9% 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 Valença do Piauí is gradually decreasing during September, decreasing from 11.1 miles per hour to 10.2 miles per hour over the course of the month. For reference, on August 9, the windiest day of the year, the daily average wind speed is 11.3 miles per hour, while on March 31, the calmest day of the year, the daily average wind speed is 5.7 miles per hour. The hourly average wind direction in Valença do Piauí throughout September is predominantly from the east, with a peak proportion of 84% on September 19. 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 Valença do Piauí 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 Valença do Piauí are very rapidly increasing during September, increasing by 940°F, from 1,885°F to 2,824°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 Valença do Piauí is essentially constant during September, remaining within 0.2 kWh of 7.2 kWh throughout. TopographyFor the purposes of this report, the geographical coordinates of Valença do Piauí are -6.407 deg latitude, -41.746 deg longitude, and 1,102 ft elevation. The topography within 2 miles of Valença do Piauí contains only modest variations in elevation, with a maximum elevation change of 358 feet and an average elevation above sea level of 1,103 feet. Within 10 miles contains only modest variations in elevation (1,050 feet). Within 50 miles contains very significant variations in elevation (2,001 feet). The area within 2 miles of Valença do Piauí is covered by shrubs (40%), trees (33%), and grassland (21%), within 10 miles by trees (51%) and shrubs (34%), and within 50 miles by trees (42%) and shrubs (40%). Data SourcesThis report illustrates the typical weather in Valença do Piauí, 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, Teresina Airport, in our network suitable to be used as a proxy for the historical temperature and dew point records of Valença do Piauí. At a distance of 192 kilometers from Valença do Piauí, further than our threshold of 150 kilometers, this station is deemed insufficiently nearby to be relied upon as our primary source for temperature and dew point records. Consequently, the station records are blended with interpolated values from NASA's MERRA-2 satellite-era reanalysis , and both are corrected for elevation differences according to the International Standard Atmosphere . The weight assigned to the MERRA-2 value depends on the distance from Valença do Piauí to the nearest station, increasing from 0% at 150 kilometers to 100% at 200 kilometers. In this case, the MERRA-2 weight is 45%, making the weight assigned to the weather station 55%. 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. |