Original article (in Croatian) was published on 28/5/2026; Author: Anja Vladisavljević
A red sky is fully explained by the laws of physics. It results from the distance sunlight must travel through Earth’s atmosphere.
White streaks across the sky are a frequent source of alarm for proponents of the chemtrails conspiracy theory. More recently, vivid red sunsets have also been added to the list of supposedly suspicious phenomena. According to these conspiracy theorists, an intensely red sunset is evidence of “spraying.”
“RIGHT NOW, 25 MAY 2026, RTL.hr RTL Direkt.
PROGRAMMING AND CONDITIONING PEOPLE THROUGH THE MEDIA TO ACCEPT RED SUNSETS AS NORMAL, WHEN IN REALITY THIS IS A BLOODY AND SICK SUNSET AFTER A WHOLE DAY OF SPRAYING WITH CHEMTRAILS, THAT IS, HEAVY METALS AND POISONS. BUT 90–95% OF PEOPLE DON’T SEE THIS. THEY ARE ASLEEP AND BELIEVE THE MEDIA,” reads a Facebook post published on May 25 by self-described “chemtrail hunter” Damir Toplek (archived here).
The post includes a screenshot from the television programme RTL Direkt, showing presenter Mojmira Pastorčić interviewing climatologist and atmospheric physicist Branko Grisogono while a photograph of a vivid red sunset is displayed on the studio screen behind them.
The programme aired on May 25, 2026, during a period of unusually hot weather and above-average temperatures for May. Grisogono was discussing the effects of climate change on weather patterns and the increasing frequency of extreme weather events. Various images and graphics were shown on the screen throughout the interview, including the photograph of the red sunset.
Scientists have repeatedly debunked the theory
According to the narrative promoted by supporters of this decades-old conspiracy theory, the trails left behind aircraft are evidence of a secret plot by a powerful group to control the weather or, in its more extreme form, to chemically “spray” the environment and the population.
As Faktograf has previously explained, it has been scientifically established that these white trails – known as contrails or condensation trails – form under specific atmospheric conditions behind aircraft jet engines. They typically occur when aircraft fly above approximately 8,000 metres, where air temperatures are below -40°C. This is why such trails do not normally appear during take-off or landing, except under exceptionally cold conditions near the ground. When the surrounding air is sufficiently cold, the trail behind an aircraft consists of tiny ice crystals.
Contrails can take many different forms – including straight lines, grid-like or criss-cross patterns, curved, spiral or fragmented shapes – depending on atmospheric conditions, wind patterns and aircraft flight paths. Although they may sometimes appear unusual, they are not a cause for concern.
Contrails may disappear quickly. However, as the Croatian Meteorological and Hydrological Service (DHMZ) previously explained to Faktograf, when cirrus or cirrostratus clouds are present, they may persist for several hours. If the surrounding air is very dry, the ice crystals rapidly sublimate into water vapour and become invisible.
These findings have been confirmed by numerous scientists. A well-known 2016 study published in Environmental Research Letters surveyed leading geochemists and found that 98.7% of respondents (76 out of 77) had never encountered evidence supporting the existence of a “secret large-scale atmospheric spraying programme” such as the alleged chemtrails operation. The surveyed scientists concluded that the white streaks observed in the sky are fully explained by established atmospheric processes, including the normal formation of aircraft contrails.
Light waves, not “poisoning”
The dramatic red, orange or pink colours seen during sunset have nothing whatsoever to do with chemicals in the atmosphere. They are entirely the result of a physical phenomenon known as Rayleigh scattering.
While investigating a similar claim previously, Faktograf asked DHMZ to explain why the sky turns red at sunset. In its response, the agency explained that the phenomenon is “a consequence of the distance that sunlight must travel through Earth’s atmosphere,” rather than the result of chemtrails or toxic heavy metals, as falsely claimed in the Facebook post.
“Sunlight travels from the Sun and passes through Earth’s atmosphere in invisible waves. The light we perceive as white is actually composed of different colours with different wavelengths. Blue light, for example, has a short wavelength, while red light has a longer wavelength.
As these light waves enter Earth’s atmosphere, they begin scattering in all directions after colliding with atoms, air molecules, haze particles, aerosols and similar substances. This process is known as Rayleigh scattering.
The degree of scattering depends on wavelength. Light with shorter wavelengths scatters much more than light with longer wavelengths. Blue light therefore scatters approximately four times more than red light. This is why the sky appears blue,” DHMZ explained.
“However, when the Sun is low in the sky – that is, close to the horizon – its light has to travel a much longer path through Earth’s atmosphere. This means that most of the short-wavelength light, such as blue light, has already been scattered before it reaches our eyes because it has travelled a much greater distance.
What remains are the longer wavelengths at the red end of the visible spectrum, which we perceive as orange or red. When the atmosphere contains large amounts of particles or water vapour, the intensity of the red colour becomes particularly strong,” DHMZ concluded.
In conclusion, the red sunset shown in the background of a television programme was neither “sick” nor unusual, nor was it caused by the nonexistent phenomenon known as chemtrails. A red sky is fully explained by the laws of physics and results from the greater distance that sunlight must travel through Earth’s atmosphere.
