Average Weather in Rosario Argentina
In Rosario, the summers are warm, humid, wet, and mostly clear and the winters are short, cold, and partly cloudy. Over the course of the year, the temperature typically varies from 42°F to 87°F and is rarely below 30°F or above 95°F.
Based on the tourism score, the best times of year to visit Rosario for warm-weather activities are from late January to mid April and from early October to late December.
The hot season lasts for 3.5 months, from November 25 to March 8, with an average daily high temperature above 82°F. The hottest day of the year is January 14, with an average high of 87°F and low of 67°F.
The cool season lasts for 2.9 months, from May 21 to August 18, with an average daily high temperature below 66°F. The coldest day of the year is July 18, with an average low of 42°F and high of 61°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
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
In Rosario, 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 Rosario begins around August 29 and lasts for 7.9 months, ending around April 26. On February 2, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 74% of the time, and overcast or mostly cloudy 26% of the time.
The cloudier part of the year begins around April 26 and lasts for 4.1 months, ending around August 29. On May 30, the cloudiest day of the year, the sky is overcast or mostly cloudy 48% of the time, and clear, mostly clear, or partly cloudy 52% of the time.
Cloud Cover Categories
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. The chance of wet days in Rosario varies throughout the year.
The wetter season lasts 6.9 months, from September 28 to April 23, with a greater than 22% chance of a given day being a wet day. The chance of a wet day peaks at 34% on December 7.
The drier season lasts 5.1 months, from April 23 to September 28. The smallest chance of a wet day is 9% on July 19.
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 34% on December 7.
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 of the year. Rosario experiences extreme seasonal variation in monthly rainfall.
Rain falls throughout the year in Rosario. The most rain falls during the 31 days centered around February 22, with an average total accumulation of 5.4 inches.
The least rain falls around July 7, with an average total accumulation of 0.9 inches.
Average Monthly Rainfall
The length of the day in Rosario varies significantly over the course of the year. In 2020, the shortest day is June 20, with 9 hours, 59 minutes of daylight; the longest day is December 21, with 14 hours, 20 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:46 AM on December 5, and the latest sunrise is 2 hours, 19 minutes later at 8:06 AM on June 30. The earliest sunset is at 6:02 PM on June 11, and the latest sunset is 2 hours, 13 minutes later at 8:15 PM on January 8.
Daylight saving time (DST) is not observed in Rosario during 2020.
Sunrise & Sunset with Twilight
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.
Rosario experiences significant seasonal variation in the perceived humidity.
The muggier period of the year lasts for 5.4 months, from November 7 to April 20, during which time the comfort level is muggy, oppressive, or miserable at least 13% of the time. The muggiest day of the year is February 8, with muggy conditions 50% of the time.
The least muggy day of the year is July 17, when muggy conditions are essentially unheard of.
Humidity Comfort Levels
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 in Rosario experiences mild seasonal variation over the course of the year.
The windier part of the year lasts for 5.1 months, from July 8 to December 11, with average wind speeds of more than 8.2 miles per hour. The windiest day of the year is September 12, with an average hourly wind speed of 9.2 miles per hour.
The calmer time of year lasts for 6.9 months, from December 11 to July 8. The calmest day of the year is February 29, with an average hourly wind speed of 7.3 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Rosario varies throughout the year.
The wind is most often from the north for 4.1 months, from March 28 to July 30, with a peak percentage of 39% on May 14. The wind is most often from the south for 1.4 months, from July 30 to September 11, with a peak percentage of 35% on September 8. The wind is most often from the east for 6.5 months, from September 11 to March 28, with a peak percentage of 39% on January 1.
Best Time of Year to Visit
To characterize how pleasant the weather is in Rosario throughout the year, we compute two travel scores.
The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best times of year to visit Rosario for general outdoor tourist activities are from late January to mid April and from early October to late December, with a peak score in the third week of November.
The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Rosario for hot-weather activities is from early December to early March, with a peak score in the second week of January.
For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.
Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.
Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.
Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.
Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.
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 in Rosario typically lasts for 9.4 months (286 days), from around August 24 to around June 7, rarely starting after September 17, or ending before May 11.
Time Spent in Various Temperature Bands and the Growing Season
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.
Based on growing degree days alone, the first spring blooms in Rosario should appear around July 22, only rarely appearing before July 15 or after August 4.
Growing Degree Days
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 extreme seasonal variation over the course of the year.
The brighter period of the year lasts for 3.6 months, from October 27 to February 15, with an average daily incident shortwave energy per square meter above 6.7 kWh. The brightest day of the year is January 5, with an average of 7.7 kWh.
The darker period of the year lasts for 3.4 months, from April 30 to August 11, with an average daily incident shortwave energy per square meter below 3.7 kWh. The darkest day of the year is June 20, with an average of 2.7 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Rosario are -32.947 deg latitude, -60.639 deg longitude, and 125 ft elevation.
The topography within 2 miles of Rosario contains only modest variations in elevation, with a maximum elevation change of 184 feet and an average elevation above sea level of 69 feet. Within 10 miles also contains only modest variations in elevation (230 feet). Within 50 miles contains only modest variations in elevation (577 feet).
The area within 2 miles of Rosario is covered by artificial surfaces (38%), water (27%), and trees (11%), within 10 miles by cropland (27%) and trees (16%), and within 50 miles by cropland (54%) and herbaceous vegetation (15%).
This report illustrates the typical weather in Rosario, 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 is only a single weather station, Rosario International Airport, in our network suitable to be used as a proxy for the historical temperature and dew point records of Rosario.
At a distance of 14 kilometers from Rosario, 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 Rosario 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.
All 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 © 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.