Climate and Average Weather Year Round in San Isidro Argentina

In San Isidro, the summers are long and hot; the winters are short, cool, and dry; and it is mostly clear year round. Over the course of the year, the temperature typically varies from 42°F to 92°F and is rarely below 33°F or above 100°F.

Based on the tourism score, the best times of year to visit San Isidro for warm-weather activities are from early March to early May and from early September to late November.

The hot season lasts for 4.3 months, from October 31 to March 9, with an average daily high temperature above 87°F. The hottest month of the year in San Isidro is January, with an average high of 91°F and low of 72°F.

The cool season lasts for 2.6 months, from May 19 to August 7, with an average daily high temperature below 71°F. The coldest month of the year in San Isidro is July, with an average low of 43°F and high of 67°F.

In San Isidro, the average percentage of the sky covered by clouds experiences mild seasonal variation over the course of the year.

The clearer part of the year in San Isidro begins around July 10 and lasts for 5.5 months, ending around December 28.

The clearest month of the year in San Isidro is September, during which on average the sky is clear, mostly clear, or partly cloudy 81% of the time.

The cloudier part of the year begins around December 28 and lasts for 6.5 months, ending around July 10.

The cloudiest month of the year in San Isidro is June, during which on average the sky is overcast or mostly cloudy 33% 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 San Isidro varies significantly throughout the year.

The wetter season lasts 4.9 months, from November 8 to April 4, with a greater than 18% chance of a given day being a wet day. The month with the most wet days in San Isidro is January, with an average of 9.7 days with at least 0.04 inches of precipitation.

The drier season lasts 7.1 months, from April 4 to November 8. The month with the fewest wet days in San Isidro is August, with an average of 0.7 days with at least 0.04 inches of precipitation.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. The month with the most days of rain alone in San Isidro is January, with an average of 9.7 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 33% on January 7.

Rainfall

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. San Isidro experiences significant seasonal variation in monthly rainfall.

The rainy period of the year lasts for 7.4 months, from September 24 to May 4, with a sliding 31-day rainfall of at least 0.5 inches. The month with the most rain in San Isidro is January, with an average rainfall of 3.3 inches.

The rainless period of the year lasts for 4.6 months, from May 4 to September 24. The month with the least rain in San Isidro is August, with an average rainfall of 0.1 inches.

The length of the day in San Isidro varies over the course of the year. In 2024, the shortest day is June 20, with 10 hours, 20 minutes of daylight; the longest day is December 21, with 13 hours, 58 minutes of daylight.

The earliest sunrise is at 6:17 AM on December 2, and the latest sunrise is 1 hour, 59 minutes later at 8:16 AM on July 1. The earliest sunset is at 6:33 PM on June 9, and the latest sunset is 1 hour, 52 minutes later at 8:25 PM on January 10.

Daylight saving time (DST) is not observed in San Isidro during 2024.

The figure below presents a compact representation of key lunar data for 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.

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.

San Isidro experiences significant seasonal variation in the perceived humidity.

The muggier period of the year lasts for 4.6 months, from November 22 to April 9, during which time the comfort level is muggy, oppressive, or miserable at least 9% of the time. The month with the most muggy days in San Isidro is January, with 10.3 days that are muggy or worse.

The least muggy day of the year is August 1, when muggy conditions are essentially unheard of.

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 San Isidro experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 6.0 months, from August 23 to February 22, with average wind speeds of more than 7.5 miles per hour. The windiest month of the year in San Isidro is November, with an average hourly wind speed of 9.1 miles per hour.

The calmer time of year lasts for 6.0 months, from February 22 to August 23. The calmest month of the year in San Isidro is June, with an average hourly wind speed of 6.0 miles per hour.

The predominant average hourly wind direction in San Isidro is from the north throughout the year.

To characterize how pleasant the weather is in San Isidro 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 San Isidro for general outdoor tourist activities are from early March to early May and from early September to late November, with a peak score in the second week of April.

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 San Isidro for hot-weather activities is from late October to late March, with a peak score in the first week of December.

Methodology

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 San Isidro typically lasts for 11 months (342 days), from around July 16 to around June 23, rarely starting after August 21, or ending before May 26.

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 San Isidro should appear around July 15, only rarely appearing before July 11 or after July 22.

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 significant seasonal variation over the course of the year.

The brighter period of the year lasts for 3.5 months, from October 18 to February 4, with an average daily incident shortwave energy per square meter above 7.2 kWh. The brightest month of the year in San Isidro is December, with an average of 8.0 kWh.

The darker period of the year lasts for 3.2 months, from April 30 to August 5, with an average daily incident shortwave energy per square meter below 4.6 kWh. The darkest month of the year in San Isidro is June, with an average of 3.7 kWh.

For the purposes of this report, the geographical coordinates of San Isidro are -28.463 deg latitude, -65.726 deg longitude, and 1,699 ft elevation.

The topography within 2 miles of San Isidro contains only modest variations in elevation, with a maximum elevation change of 404 feet and an average elevation above sea level of 1,710 feet. Within 10 miles contains only modest variations in elevation (4,980 feet). Within 50 miles also contains extreme variations in elevation (13,947 feet).

The area within 2 miles of San Isidro is covered by shrubs (29%), cropland (27%), grassland (23%), and trees (21%), within 10 miles by shrubs (59%) and trees (26%), and within 50 miles by trees (37%) and shrubs (34%).