Australia weather by month

In Sydney, the average share of the sky covered by clouds shows moderate seasonal variation over the course of the year.

The clearer part of the year begins around June 20 and lasts for 3.9 months, ending around October 17. The clearest month is August, when the sky is clear, mostly clear, or partly cloudy 78% of the time on average.

The cloudier part of the year begins around October 18 and lasts for 5.2 months, ending around March 24. The cloudiest month is December, when it is overcast or mostly cloudy 45% of the time.

This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.

Wind in Sydney is steady company: average speeds sit near 18 km/h — light breeze — in every month of the year, with no meaningful windy or calm season.

Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.

Sydney receives about 4.7 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 2.5 and 7.0 kWh/m².

The brighter stretch of the year lasts 6.2 months, from around Sep 11 to Mar 18. The brightest month is December, averaging about 6.7 kWh/m² (intense).

The dimmest month is June, down near 2.5 kWh/m² — roughly 63% less than the December peak.