New Zealand weather by month

In Auckland, 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 February 17 and lasts for 6.9 months, ending around September 15. The clearest month is August, when the sky is clear, mostly clear, or partly cloudy 54% of the time on average.

The cloudier part of the year begins around September 16 and lasts for 5.1 months, ending around February 16. The cloudiest month is November, when it is overcast or mostly cloudy 63% 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 Auckland is typically light breeze, near 18 km/h, and varies little with the seasons.

The windier part of the year lasts 4.7 months, from around Aug 2 to Dec 22. The windiest month is October, averaging about 20 km/h (light breeze).

The calmer part of the year runs from around Dec 23 to May 15, with April the calmest month at about 16 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.

Auckland receives about 4.5 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 2.0 and 7.3 kWh/m².

The brighter stretch of the year lasts 6.0 months, from around Sep 23 to Mar 25. The brightest month is January, averaging about 6.9 kWh/m² (intense).

The dimmest month is June, down near 2.0 kWh/m² — roughly 71% less than the January peak.