The short answer
Red rain is ordinary rain carrying fine dust blown north from the Sahara, usually on southerly winds. When it dries it leaves a gritty reddish film on windows, balconies and solar panels. Rinse it off with plenty of water before wiping, because rubbing dry dust into glass can scratch it, and expect solar output to dip until panels are cleaned.
What is red rain?
A few times a year, warm southerly winds (the xlokk, or sirocco) carry fine dust from the Sahara across the Mediterranean. Sometimes it hangs in the air as a yellow haze. When it meets rain, the dust falls with the water, and as the drops evaporate they leave small brown or reddish spots and streaks everywhere: cars, balconies, windows, terraces and solar panels.
It is most noticeable in spring and autumn, but it can happen at other times too.
What it does to your windows
On glass, red rain leaves a speckled film that is especially obvious when the sun shines through the window. Because the particles are fine and slightly abrasive, the way you remove them matters:
- Do not wipe it dry. Rubbing a dry cloth over gritty dust can leave fine scratches.
- Do not use a squeegee straight away. The blade drags grit across the glass.
- Rinse first. Flood the glass with water to lift the dust, then wash, then squeegee or dry.
Frames, sills and sliding door tracks collect the most dust. Clean those too, or the next shower will wash the dust back onto the glass. See how to clean aluminium sliding door tracks.
Balconies and glass balustrades
Glass balustrades show every spot, and balcony floors turn into a reservoir of dust that splashes back up. Sweep or rinse the floor first, then clean the glass. See how to clean glass balustrades.
Maltese balconies (gallariji)
Traditional timber balconies have many small panes and old frames that do not like harsh treatment. Use plenty of water, a soft cloth and gentle pressure. Our guide to cleaning Maltese balconies goes into more detail.
What it does to solar panels
Solar panels are tilted and exposed, so they collect a full layer of dust after an episode. A light shower afterwards rarely washes them clean. More often it turns the dust into a muddy film that dries in the sun.
You will usually see it in your readings: lower production on clear days with nothing else changed. The loss continues until the panels are cleaned, so after a heavy episode it is worth checking them.
The same rules apply as for windows: rinse first with plenty of water, then use a soft brush. No pressure washers, no abrasive pads, and no walking on the panels. Our guide on how often to clean solar panels in Malta covers safe cleaning in full.
When to clean after an episode
Dust episodes often come in waves over a few days. Cleaning in the middle of one is frustrating, because the glass is dusty again within a day. A good rule of thumb:
- Wait until the haze has cleared and the wind has changed.
- Check the forecast for more southerly winds.
- Clean once the air is clear, ideally early in the morning or in the evening when glass is cool.
Simple ways to reduce the build-up
- Keep sills and tracks clean. Dust in tracks and on sills gets washed back onto glass with every shower.
- Close windows during a dust episode. It keeps the inside of the glass, and your home, cleaner.
- Book regular cleans. Homes on the seafront or near building work often keep windows on a six to eight week cycle and solar panels on a twice-yearly cycle, so a single dusty day never builds up into a heavy layer.
When to call a professional
If the glass is high up, the panels are on a roof without safe access, or you have a lot of glazing, a professional clean is safer and quicker. Specialists bring the right equipment for upper floors and roofs and rinse thoroughly to avoid scratching. clear.mt arranges window cleaning and solar panel cleaning across Malta and Gozo. Rain alone rarely does the job: see does rain clean solar panels?