Mongolia weather by month

In Ulaanbaatar, 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 September 6 and lasts for 6.2 months, ending around March 13. The clearest month is January, when the sky is clear, mostly clear, or partly cloudy 69% of the time on average.

The cloudier part of the year begins around March 14 and lasts for 5.8 months, ending around September 5. The cloudiest month is June, when it is overcast or mostly cloudy 52% 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 Ulaanbaatar is typically calm, near 9 km/h, and varies moderately with the seasons.

The windier part of the year lasts 4.1 months, from around Mar 3 to Jul 4. The windiest month is April, averaging about 12 km/h (calm).

The calmer part of the year runs from around Oct 7 to Mar 2, with January the calmest month at about 7 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.

Ulaanbaatar receives about 4.2 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 1.5 and 6.7 kWh/m².

The brighter stretch of the year lasts 6.4 months, from around Mar 10 to Sep 21. The brightest month is May, averaging about 6.5 kWh/m² (intense).

The dimmest month is December, down near 1.5 kWh/m² — roughly 76% less than the May peak.