Slovakia weather by month

In Bratislava, 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 April 13 and lasts for 6.1 months, ending around October 16. The clearest month is August, when the sky is clear, mostly clear, or partly cloudy 61% of the time on average.

The cloudier part of the year begins around October 17 and lasts for 5.8 months, ending around April 12. The cloudiest month is December, when it is overcast or mostly cloudy 73% 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 Bratislava is typically calm, near 12 km/h, and varies little with the seasons.

The windier part of the year lasts 6.0 months, from around Oct 23 to Apr 24. The windiest month is February, averaging about 13 km/h (light breeze).

The calmer part of the year runs from around May 28 to Oct 22, with August the calmest month at about 10 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.

Bratislava receives about 3.4 kWh/m² a day of solar energy on average — moderate — with a clear seasonal swing between 0.9 and 5.9 kWh/m².

The brighter stretch of the year lasts 6.0 months, from around Mar 21 to Sep 18. The brightest month is June, averaging about 5.8 kWh/m² (bright).

The dimmest month is December, down near 0.9 kWh/m² — roughly 85% less than the June peak.