Average Weather in September at Treinta Y Tres Uruguay
Daily high temperatures increase by 3°F, from 66°F to 69°F, rarely falling below 56°F or exceeding 77°F.
Daily low temperatures increase by 3°F, from 48°F to 51°F, rarely falling below 38°F or exceeding 59°F.
For reference, on January 15, the hottest day of the year, temperatures at Treinta Y Tres typically range from 64°F to 85°F, while on July 9, the coldest day of the year, they range from 44°F to 61°F.
Average High and Low Temperature in September
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.
Average Hourly Temperature in September
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The month of September at Treinta Y Tres experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 45% throughout the month.
The clearest day of the month is September 30, with clear, mostly clear, or partly cloudy conditions 56% of the time.
For reference, on June 26, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 55%, while on January 8, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 69%.
Cloud Cover Categories in September
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. At Treinta Y Tres, the chance of a wet day over the course of September is essentially constant, remaining around 25% throughout.
For reference, the year's highest daily chance of a wet day is 34% on February 12, and its lowest chance is 22% on May 11.
Probability of Precipitation in September
To 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 at Treinta Y Tres is essentially constant, remaining about 3.9 inches throughout, and rarely exceeding 7.1 inches or falling below 1.2 inches.
The highest average 31-day accumulation is 4.0 inches on September 15.
Average Monthly Rainfall in September
Over the course of September at Treinta Y Tres, the length of the day is increasing. From the start to the end of the month, the length of the day increases by 58 minutes, implying an average daily increase of 2 minutes, 1 second, and weekly increase of 14 minutes, 4 seconds.
The shortest day of the month is September 1, with 11 hours, 24 minutes of daylight and the longest day is September 30, with 12 hours, 23 minutes of daylight.
Hours of Daylight and Twilight in September
The latest sunrise of the month at Treinta Y Tres is 6:55 AM on September 1 and the earliest sunrise is 39 minutes earlier at 6:16 AM on September 30.
The earliest sunset is 6:19 PM on September 1 and the latest sunset is 19 minutes later at 6:39 PM on September 30.
Daylight saving time is not observed at Treinta Y Tres during 2019.
For reference, on December 22, the longest day of the year, the Sun rises at 5:25 AM and sets 14 hours, 21 minutes later, at 7:46 PM, while on June 21, the shortest day of the year, it rises at 7:40 AM and sets 9 hours, 57 minutes later, at 5:37 PM.
Sunrise & Sunset with Twilight in September
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 chance that a given day will be muggy at Treinta Y Tres is essentially constant during September, remaining within 1% of 3% throughout.
For reference, on February 9, the muggiest day of the year, there are muggy conditions 53% of the time, while on July 22, the least muggy day of the year, there are muggy conditions 1% of the time.
Humidity Comfort Levels in September
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
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 at Treinta Y Tres is essentially constant during September, remaining within 0.1 miles per hour of 7.0 miles per hour throughout.
For reference, on September 14, the windiest day of the year, the daily average wind speed is 7.1 miles per hour, while on May 7, the calmest day of the year, the daily average wind speed is 5.8 miles per hour.
The highest daily average wind speed during September is 7.1 miles per hour on September 14.
Average Wind Speed in September
Wind Direction in September
Treinta Y Tres 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 at Treinta Y Tres is gradually increasing during September, rising by 3°F, from 55°F to 57°F, over the course of the month.
Average Water Temperature in September
Definitions 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).
The growing season at Treinta Y Tres typically lasts for 11 months (328 days), from around July 28 to around June 20, rarely starting after August 24, or ending before May 29.
The month of September at Treinta Y Tres is more likely than not fully outside of the growing season, with the chance that a given day is in the growing season gradually increasing from 95% to 100% over the course of the month.
Time Spent in Various Temperature Bands and the Growing Season in September
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
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 at Treinta Y Tres are increasing during September, increasing by 240°F, from 343°F to 584°F, over the course of the month.
Growing Degree Days in September
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 at Treinta Y Tres is increasing during September, rising by 1.2 kWh, from 4.1 kWh to 5.3 kWh, over the course of the month.
Average Daily Incident Shortwave Solar Energy in September
For the purposes of this report, the geographical coordinates of Treinta Y Tres are -33.195 deg latitude, -54.347 deg longitude, and 177 ft elevation.
The topography within 2 miles of Treinta Y Tres contains only modest variations in elevation, with a maximum elevation change of 236 feet and an average elevation above sea level of 191 feet. Within 10 miles contains only modest variations in elevation (627 feet). Within 50 miles contains significant variations in elevation (1,283 feet).
The area within 2 miles of Treinta Y Tres is covered by grassland (77%) and cropland (11%), within 10 miles by grassland (78%) and cropland (10%), and within 50 miles by grassland (75%) and cropland (11%).
This report illustrates the typical weather at Treinta Y Tres year round, 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
Treinta Y Tres has a weather station that reported reliably enough during the analysis period that we have included it in our network. When available, historical temperature and dew point measurements are taken directly from this weather station. These records are obtained from NOAA's Integrated Surface Hourly data set, falling back on ICAO METAR records as required.
In the case of missing or erroneous measurements from this station, we fall back on records from nearby stations, adjusted according to typical seasonal and diurnal intra-station differences. For a given day of the year and hour of the day, the fallback station is selected to minimize the prediction error over the years for which there are measurements for both stations.
In this case, the only station close and reliable enough to use as a fallback is Capitán de Corbeta Carlos A. Curbelo International Airport.
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 .
Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.
The 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.