The short answer
For most homes in Malta and Gozo the best times are September or October, after the long dry summer, and again in spring before the sunniest months. Book an extra clean after a red rain episode, never just before one. On the day itself, clean early in the morning or late in the afternoon, when the glass is cool.
The short answer
In Malta and Gozo, panels get dirtiest when the sun is strongest. From May to September there is almost no rain, the air carries dust from fields, roads and building sites, and the occasional Saharan dust episode adds a fine reddish layer on top. By the end of summer most rooftop systems are wearing months of grime.
That is why we suggest two cleans a year for most homes:
- September or October, to clear the summer’s build-up before the shorter days.
- Spring, around March or April, to start the long sunny season with clean glass.
Add an extra clean after red rain when it leaves a visible muddy film. Homes near the sea, near quarries or building sites, or with lots of birds on the roof may need more. Our guide on how often to clean solar panels in Malta goes into those cases.
Why panels are dirtiest by September
Three things stack up through the Maltese summer:
- No rain. In much of Europe, regular showers rinse loose dust off panels. Here, rooftops can go from late spring to the first autumn storms with nothing but dew, which turns dust into a sticky film.
- Dust everywhere. Dry fields, construction, traffic and quarry work all put fine particles in the air. Flat roofs collect it, and panels on low frames sit right in it.
- Saharan dust. When the wind blows from the south, dust from North Africa settles across the islands. It is very fine and clings to glass. See our guide to red rain and Saharan dust.
The first autumn rain does not wash this away. Light rain mixes with the dust and leaves mud lines along the bottom frame, where water collects before it drains. Our guide on whether rain cleans solar panels explains why.
Why a spring clean pays off
The spring clean is the one people skip, but it is well timed. From April to August your panels get the longest days and the most direct sun of the year. Starting that stretch with clean glass means you are not carrying winter’s bird droppings, salt and red-rain mud into the months that matter most.
Spring is also a good time to spot problems: a cracked panel, loose cabling, a nest under the frame or a corner that never dries. A cleaner on the roof will notice these, and you can pass them to your installer.
Clean after red rain, not before
Red rain is unpredictable. A forecast may show a southerly wind and dusty skies a day or two ahead, but it is hard to say exactly when the dust will fall or how heavy it will be. If you book a clean just before, the next shower can undo it within hours.
The better rule:
- Wait until the episode has passed and the forecast is clear.
- Look at the panels from a safe spot, or check your inverter app. If you see a muddy film or output has dropped compared with similar sunny days, book a clean.
- If the dusting was light and a proper rain followed, you may be able to wait for your next scheduled clean.
Your monitoring app is the most useful tool here. Our guide on why solar output is low covers how to read it, and when a drop points to dirt rather than a fault.
The best time of day
Whoever does the cleaning, timing on the day matters:
- Early morning is ideal. The glass is cool, there may be dew to help loosen dirt, and there is time to finish before the panels heat up.
- Late afternoon works too, once the sun has dropped.
- Avoid the middle of the day, especially from May to October. Panels in full Maltese sun get far too hot to touch. Water evaporates before it can be wiped, leaving spots, and cold water on very hot glass is best avoided.
Professional cleaners plan rooftop jobs around this, which is why summer bookings often start early.
What happens if you skip a year
Nothing dramatic, usually. The panels keep working, but dirt keeps building up, especially along the lower edges and around bird droppings. Over time that dirt bakes on and is harder to remove. Bird droppings in particular can shade one part of a panel and pull down the output of that whole string.
If you have not had the panels cleaned for a year or more, the first clean may take longer. After that, a regular rhythm keeps each clean quicker. For the full picture on output, see does cleaning solar panels increase output.
Fitting it into the rest of the year
Solar cleaning sits well alongside other seasonal jobs on a Maltese home. The autumn clean can be booked with your windows and a chimney sweep before winter, and the spring clean pairs with clearing the roof drains after the storms. Our home maintenance calendar for Malta sets out the whole year.
If your panels sit on raised frames on a flat roof, read cleaning solar panels on flat roofs and raised frames for how access affects timing and safety.
Booking a clean
We arrange solar panel cleaning across Malta and Gozo, using purified water and soft brushes, at cooler times of day. Autumn fills up quickly after the summer, so it helps to get a quote in late August or early September.