Summer Weather in Riversdale South Africa

Daily high temperatures are around 79°F, rarely falling below 70°F or exceeding 89°F. The highest daily average high temperature is 81°F on January 26.

Daily low temperatures are around 61°F, rarely falling below 53°F or exceeding 68°F. The highest daily average low temperature is 63°F on February 11.

For reference, on January 26, the hottest day of the year, temperatures in Riversdale typically range from 63°F to 81°F, while on July 11, the coldest day of the year, they range from 46°F to 66°F.

The figure below shows you a compact characterization of the hourly average summer temperatures. 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.

Long Beach, United States (10,139 miles away) and Anitápolis, Brazil (4,114 miles) are the far-away foreign places with temperatures most similar to Riversdale (view comparison).

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The summer in Riversdale experiences rapidly decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 30% to 17%. The lowest chance of overcast or mostly cloudy conditions is 13% on February 11.

The clearest day of the summer is February 11, with clear, mostly clear, or partly cloudy conditions 87% of the time.

For reference, on May 10, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 42%, while on February 11, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 87%.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Riversdale, the chance of a wet day over the course of the summer is gradually increasing, starting the season at 10% and ending it at 12%.

For reference, the year's highest daily chance of a wet day is 18% on April 7, and its lowest chance is 10% on December 20.

Rainfall

To show variation within the season and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day rainfall during the summer in Riversdale is essentially constant, remaining about 1.0 inches throughout, and rarely exceeding 3.0 inches.

The lowest average 31-day accumulation is 0.8 inches on February 5.

Over the course of the summer in Riversdale, the length of the day is rapidly decreasing. From the start to the end of the season, the length of the day decreases by 1 hour, 25 minutes, implying an average daily decrease of 57 seconds, and weekly decrease of 6 minutes, 42 seconds.

The shortest day of the summer is February 28, with 12 hours, 51 minutes of daylight and the longest day is December 21, with 14 hours, 26 minutes of daylight.

The earliest sunrise of the summer in Riversdale is 5:16 AM on December 5 and the latest sunrise is 1 hour, 6 minutes later at 6:21 AM on February 28.

The latest sunset is 7:50 PM on January 6 and the earliest sunset is 38 minutes earlier at 7:12 PM on February 28.

Daylight saving time is not observed in Riversdale during 2024.

For reference, on December 21, the longest day of the year, the Sun rises at 5:20 AM and sets 14 hours, 26 minutes later, at 7:46 PM, while on June 20, the shortest day of the year, it rises at 7:40 AM and sets 9 hours, 53 minutes later, at 5:33 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.

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

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 in Riversdale is increasing during the summer, rising from 3% to 11% over the course of the season.

The highest chance of a muggy day during the summer is 14% on February 11.

For reference, on February 11, the muggiest day of the year, there are muggy conditions 14% of the time, while on May 25, the least muggy day of the year, there are muggy conditions 0% of the time.

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 Riversdale is gradually decreasing during the summer, decreasing from 11.1 miles per hour to 10.3 miles per hour over the course of the season.

For reference, on November 25, the windiest day of the year, the daily average wind speed is 11.2 miles per hour, while on April 26, the calmest day of the year, the daily average wind speed is 8.7 miles per hour.

The hourly average wind direction in Riversdale throughout the summer is predominantly from the south, with a peak proportion of 45% on January 20.

Riversdale 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 Riversdale is gradually increasing during the summer, rising by 3°F, from 67°F to 70°F, over the course of the season.

The highest average surface water temperature during the summer is 71°F on January 31.

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).

Temperatures in Riversdale 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 Riversdale are very rapidly increasing during the summer, increasing by 1,768°F, from 1,489°F to 3,256°F, over the course of the season.

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 in Riversdale is decreasing during the summer, falling by 1.2 kWh, from 8.1 kWh to 6.9 kWh, over the course of the season.

The highest average daily incident shortwave solar energy during the summer is 8.5 kWh on January 2.

For the purposes of this report, the geographical coordinates of Riversdale are -34.093 deg latitude, 21.257 deg longitude, and 397 ft elevation.

The topography within 2 miles of Riversdale contains significant variations in elevation, with a maximum elevation change of 509 feet and an average elevation above sea level of 469 feet. Within 10 miles contains significant variations in elevation (4,373 feet). Within 50 miles also contains extreme variations in elevation (7,592 feet).

The area within 2 miles of Riversdale is covered by cropland (73%), artificial surfaces (15%), and shrubs (11%), within 10 miles by cropland (73%) and shrubs (26%), and within 50 miles by shrubs (41%) and water (32%).