Guam weather by month

In Dededo Village, 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 November 4 and lasts for 7.3 months, ending around June 13. The clearest month is December, when the sky is clear, mostly clear, or partly cloudy 68% of the time on average.

The cloudier part of the year begins around June 14 and lasts for 4.7 months, ending around November 3. The cloudiest month is August, when it is overcast or mostly cloudy 88% 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 Dededo Village is typically breezy, near 24 km/h, and varies a lot with the seasons.

The windier part of the year lasts 6.1 months, from around Nov 2 to May 5. The windiest month is December, averaging about 30 km/h (windy).

The calmer part of the year runs from around May 6 to Nov 1, with September the calmest month at about 18 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.

Dededo Village receives about 5.6 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 4.9 and 6.7 kWh/m².

The brighter stretch of the year lasts 5.1 months, from around Feb 16 to Jul 20. The brightest month is April, averaging about 6.7 kWh/m² (intense).

The dimmest month is December, down near 4.9 kWh/m² — roughly 26% less than the April peak.