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Wednesday, May 14, 2025
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Understanding the Aphelion phenomenon: Debunking myths about its impact on South African winters

Yasmine Jacobs|Published

The Aphelion phenomenon does not affect our weather and season, but this is what does,

Image: IOL

Winter is coming...and so is fake news and misinformation.

In recent days, a misleading hoax has been circulating online, claiming that South Africa will experience a cold spell until August 2025 due to a phenomenon known as "Aphelion."

The message, shared widely on WhatsApp, has stirred confusion and panic, but it's important to note that this claim is entirely false.

To clear up the confusion, we take a closer look at the science behind the Aphelion phenomenon, why it doesn’t affect the weather in the way some believe, and what the real drivers of our seasons are.

What is Aphelion?

Aphelion refers to the point in Earth's orbit when the planet is farthest from the Sun.

This occurs once every year, and in 2025, it will take place on July 3rd at around 3:54 PM (UTC). However, contrary to what the hoax suggests, the fact that Earth is at its farthest point from the Sun during this time does not lead to significant changes in temperature or weather.

The Earth's orbit is slightly elliptical, meaning the distance from the Sun varies over the course of a year.

At Aphelion, Earth is about 152 million kilometres away from the Sun, as compared to its closest point—called Perihelion—when Earth is about 147 million kilometres away. So if we went according to the hoax's logic, we would deal with intense heat at the time of Perihelion, which we do not.

The difference is relatively small and doesn’t significantly affect the amount of solar radiation the Earth receives.

The Real Drivers of Seasons: Earth's Tilt, Not Its Distance from the Sun

So we have established that the distance from the sun does not affect temperature and seasons, so what does?

The key factor responsible for the seasons is Earth's axial tilt. Earth’s axis is tilted by about 23.5 degrees relative to its orbit around the Sun. This tilt means that different parts of the planet receive varying amounts of sunlight throughout the year, creating the distinct seasons.

In the Southern Hemisphere, summer occurs around December when the Southern Hemisphere is tilted toward the Sun. Winter happens around June when it is tilted away.

Those living in the Northern Hemisphere find that the opposite is true, with summer happening in June and winter in December.

The variation in Earth’s distance from the Sun during Aphelion and Perihelion has a minimal effect on temperatures or seasons. What really drives the temperature changes we experience is the angle at which sunlight hits the Earth's surface—something determined by the tilt, not the distance.

What Can We Expect from Winter 2025?

The South African Weather Service has urged South Africans not to circulate misinformation and called on residents to verify information before sharing.  

"According to our seasonal climate watch, issued on the 2nd of May 2025, minimum and maximum temperatures are expected to be above normal for most parts of the country during the winter season, above normal meaning that the temperatures are expected to be warmer than what we would get during our winter months. The Republic of South Africa will continue to be affected by different weather winter systems that are known to drop temperatures like the Cold fronts & cut off lows. In addition, the southern coastal regions are expected to have below normal temperatures for the remainder of the winter period.

 "Furthermore, the El Niño- Southern Oscillation (ENSO) returned to a neutral state and it is predicted to remain there for the foreseeable future. It is important to note that ENSO has limited influence on South Africa during the winter season and is not expected to have a significant impact. However, as winter begins the focus is over the south-western parts of the country, as well as along the east and south coastal regions. These areas are expected to receive below-normal rainfall early-, mid- and late winter.

IOL