Alonissos weather by month

When to go to Alonissos

For beach weather, look at months where the daytime average clears 25°C and rainy days stay low: July, August. December is the wettest month (96 mm, about 11 rainy days) and June the driest (14 mm). The sea is warmest in August at 25.9°C and coolest in March at 13.8°C.

Getting there

A direct flight from London Gatwick to Skiathos Island National Airport (JSI, 31 km from Patitírion) takes roughly 3 h 36 min - short-haul (up to 4.5 h) by UK standards. Time-zone: Europe/Athens.

Records and extremes, 1991-2020

The hottest day recorded in Alonissos between 1991 and 2020 reached 36.8°C on 27 June 2007; the coldest fell to -1.9°C on 13 February 2004. In August one day in ten tops 28.6°C and about 3% of days pass 30°C; in January one night in ten drops to 4.4°C or below. The wettest single month of the period was October 1994 with 252 mm, against a October average of 61 mm.

Winter and spring: layers first, swimming later

December, January and February are better for time outdoors between showers than for a beach holiday. Daytime averages sit at 12°C in December and 11°C in January and February, so pack a jacket and waterproof layer rather than relying on sunshine for warmth. March edges up to 13°C, but the sea remains cold. April makes outdoor plans easier, with 16°C days, 8 hours of sunshine and fewer rainy days than winter. May is the stronger choice for comfortably warm afternoons: days average 20°C and evenings are milder, though a light layer remains useful. The main spring catch is swimming. Even in May, the sea averages 18°C, so choose this period for being outdoors without summer warmth rather than expecting long, comfortable swims.

Summer: the strongest choice for sunshine and swimming

June offers a useful balance: average days of 24°C, sea temperatures of 23°C and 12 hours of sunshine make it a strong choice for swimming without choosing the hottest month. July brings 26°C days and the most sunshine, at 13 hours, while August is warmest, with daytime averages of 27°C and a 26°C sea. All these summer months average 2 rainy days, so rain is less likely to shape your plans than in other seasons. Keep clothing light, use sun protection and leave room for shade around midday. Nights average 24°C in July and August, so evenings offer only limited relief from the warmth.

Autumn: warm water lingers as rain becomes more likely

September keeps much of summer's appeal, with daytime and sea temperatures both averaging 24°C. Its 9 hours of sunshine leave plenty of scope for outdoor plans, although 4 rainy days make it less consistently dry than summer. October is a compromise: days average 20°C and the sea holds at 21°C, making it more inviting for swimming than spring, but 7 rainy days call for flexibility. Pack a light layer for evenings rather than treating it as full summer. By November, daytime temperatures fall to 16°C and sunshine drops to 4 hours. With the sea at 18°C, this is better suited to travellers who do not need swimming to anchor their holiday.