Galissas weather in May 2025

Q: How hot is it in Galissas in May?

Daytime temperatures usually reach 22°C in Galissas in May, falling to 15°C at night.

Q: How sunny is it in Galissas in May?

There are normally 10 hours of bright sunshine each day in Galissas in May - that's 73% of daylight hours.

Q: How warm is the sea around Galissas in May?

The average sea temperature around Galissas in May is 18°C.

Q: Does it ever rain in Galissas in May?

There are usually 3 days with some rain in Galissas in May and the average monthly rainfall is 16mm.

Expect 22°C daytime maximum temperatures in the shade with on average 10 hours of sunshine per day in Galissas in May. Check more long-term weather averages for Galissas in May before you book your next holiday to Syros in 2025/2026.

22
22°C max day temperature
10
10 hours of sunshine per day
3
3 days with some rainfall
15
15°C min night temperature
14
14 hours of daylight per day
0
No heat & humidity
16
16 mm of monthly rainfall
8
8 (Very High) UV index
18
18°C sea temperature

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The May weather guide for Syros, represented by Galissas, (Galissas) shows long term weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.

Metric (°C / mm) | Imperial (°F / inches)