Best time to visit Alonissos

The best time to visit Alonissos for a beach holiday is during summer, from June to mid-September. The peak summer months of July and August average a high of 29°C (84°F).

However, anytime from early-May to early-October is good for a range of outdoor activities. Mid-season – May, September and October – offers reasonable hotel prices and generally less crowds.

Alonissos weather

Alonissos enjoys a Mediterranean climate with hot, sunny summers and mild, wet winters. Despite winter rainfall, Alonissos is considered a year-round destination.

The Sporades are not as hot as the Cyclades. The Northern Sporades – Alonissos, Skiathos, Skopelos and Skyros – often have cold and windy periods in winter, especially the westernmost islands, such as Skiathos and Skopelos.

Summer, from June to mid-September, is hot and sunny, with little or no rainfall; maximum temperatures hover around 29°C (84°F), and occasionally higher.

Autumn, from mid-September to November, is pleasantly warm before gradually becoming cooler and windy by November.

Winter, from December to mid-March, is generally cold, with moderate to strong winds. Occasionally, it can snow. Rainfall is frequent; December sees the most rainfall during the year.

Spring, from mid-March to May, begins cold, windy and wet, before gradually become milder.

What is the best month to visit Alonissos?
July and August are the best months to visit Alonissos – the climate is perfect with hot, sunny weather and little or no rainfall.

However, the months of May through October are all good for a range of outdoor activities.

Which is the hottest month in Alonissos?
The hottest month in Alonissos is usually August, with an average daily high temperature of 29°C (84°F), with high heat and humidity, and a low of 24°C (75°F).

On the warmest days of summer – July and August – the temperature usually reaches a high of around 33°C (91°°F)

The warm season lasts from early-June to mid-September, with an average daily high temperature above 25°C (77°F).

Which is the sunniest month in Alonissos?
The sunniest month of the year in Alonissos is usually July with an average of 12 hours of sunshine per day; that's around 83% of daylight hours.

The months of June through September are the sunniest of the year.

What is the humidity in Alonissos?
Alonissos experiences significant seasonal variation in perceived humidity, with approximate average relative humidity calculated at between 59% – 72% over the course of the year.

The more humid time of year lasts from mid-June through to mid-September, when you can expect the comfort level to be muggy at least 12% of the time.

The month with the most muggy days in Alonissos is August, with around 14 days that are muggy.

We derive the humidity comfort level from the dew point temperature, which measures moisture content in the air. A higher dew point feels muggy and uncomfortable.

November through April is generally comfortable, with no days in any month that are muggy.

When is the sea warmest in Alonissos?
The sea is usually at its warmest in Alonissos in August when the water temperature reaches 25°C (77°F), which is warm for swimming.

The sea temperature is comfortable for swimming from July through to September. June is a bit cool for swimming.

Which is the coldest month in Alonissos?
The coldest month in Alonissos is January, with an average high temperature of 14°C (57°F) and an average low temperature of 7°C (44°F).

The cool winter season lasts from late-November to late-March, with an average daily high temperature below 15°C (59°F).

Which month has the most rain in Alonissos?
December is usually the wettest month in Alonissos with 95mm (3.7in) of rainfall on average. There are normally 12 days in December with some rain.

The wet season lasts from early-October to mid-April, with a greater than 14% chance of a given day being a wet day.

The drier season lasts from mid-April to early-October; the months with the least rainfall in Alonissos is July and August.

Which is the windiest month in Alonissos?
The windiest month of the year in Alonissos is January, with an average hourly wind speed of 19 kilometres per hour (10 knots; 12 mph).

The windy part of the year lasts from mid-October to late-March, with average wind speeds of more than 15 kilometres per hour (8 knots; 10 mph).

The less-windy time of year lasts from late-March through to mid-October. The calmest month of the year in Alonissos is June, with an average hourly wind speed of 11 kilometres per hour (6 knots; 8 mph).

The predominant average hourly wind direction in Alonissos is from the north throughout the year.

Alonissos Weather Averages

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average high temperature (°C)
12 12 14 17 22 27 29 29 25 21 17 13
Average low temperature (°C)
7 8 10 13 17 22 24 24 20 17 13 9
Average daily sunshine (hrs)
4 5 6 8 9 11 12 11 9 7 5 3
Average daily daylight (hrs)
10 11 12 13 14 15 14 13 12 11 10 9
Comfort level
Cold, no heat & humidity Cold, no heat & humidity Cold, no heat & humidity No heat & humidity Low heat & humidity icon Moderately hot icon Moderately hot icon Moderately hot icon Low heat & humidity icon No heat & humidity No heat & humidity Cold, no heat & humidity
Average relative humidity (%)
71 69 66 67 63 60 59 60 65 71 72 72
UV Index (max)
2 3 4 6 8 9 9 8 6 4 2 2
Average days of rainfall (≥1mm)
10 9 8 7 6 4 2 2 5 7 10 12
Average monthly rainfall (mm)
80 70 60 40 40 25 20 25 40 70 70 95
Average wind speed (km/h)
19 19 16 14 12 11 12 13 13 15 17 18
Average sea temperature (°C)
14 14 13 14 18 22 24 25 24 21 18 15
Patitírion, Alonissos, Greece

Holiday seasons

High season: July and August, when hotel and restaurant prices sky-rocket.

Mid season: From March to June and from September to October – the temperature is cooler, hotel prices are more reasonable and the crowds non-existent.

Note: The winter off-season, from November through February, is generally quiet everywhere; many hotels, restaurants and bars close down and the beaches are deserted. Ferry and air services are dramatically reduced.

Source: Meteorological data for Alonissos is based on weather statistics gathered for the 30-year period 1991 to 2020 by the Hellenic National Meteorological Service (HNMS).

Advice on the best time to visit a particular destination is based on average local weather statistics, when the weather conditions are generally better than at other times of the year. We consider high and low temperatures, risk of rain (and thunderstorms, etc.), amount of sunshine and sea temperature. For general outdoor activities we favour clear, rainless days with a temperature range between 18°C (64°F) and 27°C (80°F); and for hot-weather activities we favour clear, rainless days with a temperature range between 24°C (75°F) and 32°C (89°F). Often, the best times to visit correspond to high season and therefore involve higher prices.

More about Alonissos…

Latest update: Best time to visit Alonissos: 11 May, 2024

Disclaimer: The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data and conditions at any given location and time are unpredictable and variable. We assume no responsibility and can not be held legally responsible for any decisions made on the basis of the information presented on this site.