Yemen weather by month

In Sanaa, 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 20 and lasts for 6.9 months, ending around April 18. The clearest month is December, when the sky is clear, mostly clear, or partly cloudy 93% of the time on average.

The cloudier part of the year begins around April 19 and lasts for 5.1 months, ending around September 19. The cloudiest month is July, when it is overcast or mostly cloudy 64% 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 Sanaa is typically calm, near 7 km/h, and varies little with the seasons.

The windier part of the year lasts 2.4 months, from around Sep 1 to Nov 12. The windiest month is October, averaging about 9 km/h (calm).

The calmer part of the year runs from around Jun 26 to Aug 31, with August the calmest month at about 6 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.

Sanaa receives about 6.2 kWh/m² a day of solar energy — intense — and it stays remarkably steady, holding between 5.5 and 6.8 kWh/m² all year. For solar panels, output here is a flat line, not a seasonal wave.