Colourful beach huts with TESUP flexible solar panels on their roofs, an Atlas wind turbine on the sand and a Magnum turbine by the sea, with the headline: summer is coming
October 28, 2026

On 21 December the sun reaches its highest point of the year across the southern hemisphere. In Sydney and Cape Town it climbs to 80 degrees above the horizon at midday and stays up for almost 14 and a half hours. On the shortest day in June it managed 33 degrees and less than 10 hours. For solar panels, the best months of the year are about to begin.

Longer days, higher sun

Every city south of the equator gets the same summer gift: more hours of daylight and a sun that climbs much higher in the sky. Melbourne gains more than five hours of daylight between the shortest and the longest day. Auckland gains five. In São Paulo, which sits almost exactly on the Tropic of Capricorn, the midday sun on 21 December stands practically straight overhead.

Chart comparing daylight hours on 21 June and 21 December in Sydney, Melbourne, Auckland, Cape Town and São Paulo, with the midday sun height for each
Daylight and midday sun height on the shortest and the longest day of the year.

A higher sun means more energy

Longer days are only half of the story. When the sun is high, its light hits the ground more directly and travels through less air on the way. Put the two together and, before clouds are counted, a flat surface in Sydney or Cape Town receives about 2.7 times as much solar energy on 21 December as on 21 June. In Melbourne and Auckland it is more than three times as much.

Bar chart: solar energy reaching a flat surface on 21 December compared with 21 June, about 3.2 times in Melbourne, 3.1 in Auckland, 2.7 in Sydney and Cape Town, and 2 in São Paulo
21 December against 21 June: solar energy reaching a flat surface, before clouds.

Solar where rigid panels cannot go

Our flexible solar panels are made for exactly this season. Each panel delivers 230 W from about one square metre, and they ship as a pair for 460 W in total. They are thin and light, bend to a curve and fix down without a heavy frame, so they suit caravans, boats, sheds, garden buildings and curved or weight-sensitive roofs. The ETFE front sheet is anti-reflective and self-cleaning.

A row of colourful beach huts with TESUP flexible solar panels on their roofs, and a Magnum wind turbine turning by the sea
Flexible panels go where a rigid frame cannot: light roofs, curves and small buildings.

The wind does not take summer off

Summer is also the season of the sea breeze. On hot afternoons the land warms faster than the ocean, and cooler air flows in from the coast. Cape Town's famous south-easter, the Cape Doctor, blows mostly from spring through summer. And when the sun sets, the panels stop while the wind keeps going. Atlas with Low-Wind blades starts turning at just 2 metres per second, so it keeps working through the evening and the night.

Close-up of a TESUP Atlas vertical wind turbine on the sand in front of colourful beach huts on a sunny day
Atlas on the beach: when the sun goes down, the wind takes over.

Sun by day, wind round the clock

This is why household wind turbines and flexible solar panels work so well together. From December to February the sun does the heavy lifting during the day. Atlas and Magnum cover the evenings, the nights and the cloudy spells, and they take the lead again when the days get short. Together they spread your home's own power across the day and across the year.

Daylight hours and midday sun height: calculated with standard solar position formulas for 21 June and 21 December 2026. Solar energy: daily total reaching a horizontal surface at the top of the atmosphere, calculated for each city. Product figures: TESUP product data.

Make the long days count

Flexible solar panels for the sunny hours. Atlas catches wind from any direction, and Magnum is made for open, steady wind.

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