Hong Kong weather by month

In Hong Kong, the average share of the sky covered by clouds shows significant seasonal variation over the course of the year.

The clearer part of the year begins around September 9 and lasts for 5.0 months, ending around February 8. The clearest month is October, when the sky is clear, mostly clear, or partly cloudy 70% of the time on average.

The cloudier part of the year begins around February 9 and lasts for 7.0 months, ending around September 8. The cloudiest month is June, when it is overcast or mostly cloudy 81% 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.

Across the year, average wind speed in Hong Kong is typically light breeze, near 17 km/h, and varies moderately with the seasons.

The windier part of the year lasts 6.0 months, from around Oct 1 to Mar 31. The windiest month is December, averaging about 20 km/h (light breeze).

The calmer part of the year runs from around Apr 1 to Sep 30, with August the calmest month at about 14 km/h.

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.

Hong Kong receives about 4.5 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 3.4 and 5.7 kWh/m².

The brighter stretch of the year lasts 6.9 months, from around Apr 2 to Oct 29. The brightest month is July, averaging about 5.6 kWh/m² (bright).

The dimmest month is December, down near 3.4 kWh/m² — roughly 39% less than the July peak.