Climate - Syros (Greece)

Syros: Temperatures - Precipitation - Sunshine hours - Sea temperatures - Best time - Weather by month


In Syros, a small Greek island belonging to the archipelago of the Cyclades, the climate is Mediterranean, with mild, rainy winters and warm, sunny summers.
The island is windy. In autumn and winter, the wind blows in periods of bad weather, either the mild southerly wind preceding Atlantic disturbances or the northwest wind brought by cold outbreaks from the Balkan Peninsula. On the other hand, in summer, the Meltemi dominates (see below).
The daily average temperature ranges from 11.5 °C (51 °F) in January to 27 °C (80.5 °F) in July. Here are the average temperatures.

Rainfall follows the Mediterranean pattern, in fact, it is concentrated from October to March, and is not abundant, since it amounts to 475 millimeters (18.5 inches) per year, and this is confirmed by the aridity of the landscape. Here is the average precipitation.

Winter, from December to mid-March, is mild, rainy and windy. The wind, frequent and sometimes stormy, heightens the feeling of cold. There is a moderate amount of mild days, with highs around 16/18 °C (61/64 °F), but the island is located quite to the north and close enough to the mainland to receive cold air with some frequency, to the point that there can be cold days, with highs below 10 °C (50 °F), and occasionally, even snow can fall.



Spring, from mid-March to May, is mild and sunny, but it is often windy. By mid-May, the Meltemi starts to blow, an insistent wind, cool and dry, which blows from the north for some days in a row, especially during the day, but sometimes even at night.

Summer, from June to mid-September, is warm and sunny, but also windy. The Meltemi blows for long periods, especially in July and August, and it's stronger in the afternoon, but it can insist also in the evening. With this wind, the maximum temperature usually remains below or around 30 °C (86 °F), and heat waves are generally less intense than in other parts of Greece.

Autumn, from mid-September to November, is initially warm and sunny, and gradually becomes cooler and more rainy. Autumn too is windy: as long as the weather is good, the Meltemi still blows, while later, the wind blows along with autumnal disturbances.



The amount of sunshine in Syros is great in summer, when clear skies prevail, while in winter, sunny periods alternate with others characterized by clouds and rain. Here are the average sunshine hours per day.

The temperature of the Aegean Sea is never very high, since the wind that blows in summer tends to keep it a bit low, however, it reaches a maximum of 23.5 °C (74 °F) in July and September and 24 °C (75 °F) in August; in June, it's still a bit cool. Here are the average sea temperatures.

Best Time

The best time to go to Syros for a beach holiday is the summer, from June to mid-September. In June, as we mentioned, the sea is cooler than in midsummer.
It's better to bring a sweatshirt for cool evenings, which occur mainly in June, but given the intensity of the wind, those who are sensitive to cold can feel a little cool even in July and August.
If you want to visit towns and go hiking and walking, spring is fine, in April and May, but since it is normally not too hot, you can usually walk around the island also in summer, except in the rare hot and windless days.

Back to the Cyclades Islands.

Syros - Weather by month

Based on the period 1998-2020

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In January, the coldest month of the year, the weather in Syros is usually mild. The average temperature is of 11.4 °C (52 °F), with a minimum of 9.6 °C (49.2 °F) and a maximum of 13.2 °C (55.7 °F).
On the coldest nights of the month, the temperature usually drops to around 4 °C (39.5 °F). However, it dropped to 0 °C (32 °F) in January 2004.
On the warmest days of the month, the temperature usually reaches around 17.5 °C (63.5 °F). However, it reached 19 °C (66.2 °F) in January 2002.
Precipitation amounts to 90 mm (3.5 in), distributed over 10 days.
The day lasts on average 9 hours and 55 minutes.
There are on average 3.5 hours of sunshine per day. So, the sun shines 37% of the time.
The average humidity is 70%.
The average wind speed is 22 kph (13 mph).
The average sea temperature is of 16 °C (61 °F). Therefore, the sea is cold for swimming.

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In February, the weather in Syros is usually mild. The average temperature is of 11.9 °C (53 °F), with a minimum of 9.9 °C (49.7 °F) and a maximum of 13.9 °C (57 °F).
On the coldest nights of the month, the temperature usually drops to around 4.5 °C (40 °F). However, it dropped to -1 °C (30.2 °F) in February 2004.
On the warmest days of the month, the temperature usually reaches around 18.5 °C (65 °F). However, it reached 22 °C (71.6 °F) in February 2016.
Precipitation amounts to 65 mm (2.6 in), distributed over 8 days.
The day lasts on average 10 hours and 50 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 48% of the time.
The average humidity is 70%.
The average wind speed is 22 kph (14 mph).
The average sea temperature is of 15.5 °C (60 °F). Therefore, the sea is cold for swimming.

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In March, the weather in Syros is usually mild. The average temperature is of 13.6 °C (57 °F), with a minimum of 11.5 °C (52.7 °F) and a maximum of 15.8 °C (60.4 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 7 °C (44.5 °F). However, it dropped to 2 °C (35.6 °F) in March 2003.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 20.5 °C (69 °F). However, it reached 25 °C (77 °F) in March 2001.
Precipitation amounts to 55 mm (2.2 in), distributed over 7 days.
The day lasts on average 12 hours and 0 minutes.
There are on average 6.5 hours of sunshine per day. So, the sun shines 53% of the time.
The average humidity is 68%.
The average wind speed is 20 kph (12 mph).
The average sea temperature is of 15.5 °C (59.5 °F). Therefore, the sea is cold for swimming.

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In April, the weather in Syros is usually very mild. The average temperature is of 16.2 °C (61 °F), with a minimum of 13.8 °C (56.8 °F) and a maximum of 18.6 °C (65.6 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 10 °C (50.5 °F). However, it dropped to 7 °C (44.6 °F) in April 2003.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 24 °C (75 °F). However, it reached 28 °C (82.4 °F) in April 2016.
Precipitation amounts to 25 mm (1 in), distributed over 5 days.
The day lasts on average 13 hours and 10 minutes.
There are on average 8.5 hours of sunshine per day. So, the sun shines 66% of the time.
The average humidity is 65%.
The average wind speed is 18 kph (11 mph).
The average sea temperature is of 16 °C (61 °F). Therefore, the sea is cold for swimming.

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In May, the weather in Syros is usually warm. The average temperature is of 20.5 °C (69 °F), with a minimum of 17.9 °C (64.2 °F) and a maximum of 23.1 °C (73.6 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 14 °C (57.5 °F). However, it dropped to 12 °C (53.6 °F) in May 2000.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 28.5 °C (83.5 °F). However, it reached 34 °C (93.2 °F) in May 2020.
Precipitation amounts to 15 mm (0.6 in), distributed over 3 days.
The day lasts on average 14 hours and 10 minutes. So the days are long.
There are on average 9.5 hours of sunshine per day. So, the sun shines 68% of the time.
The average humidity is 61%.
The average wind speed is 15 kph (9 mph).
The average sea temperature is of 18.5 °C (65.5 °F). Therefore, the sea is very cool for swimming.

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In June, the weather in Syros is usually warm to hot. The average temperature is of 24.9 °C (77 °F), with a minimum of 22.3 °C (72.2 °F) and a maximum of 27.4 °C (81.3 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 18 °C (65 °F). However, it dropped to 16 °C (60.8 °F) in June 2012.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 33 °C (91.5 °F). However, it reached 39 °C (102.2 °F) in June 2007.
Precipitation amounts to only 5 mm (0.2 in), distributed over 2 days.
The day lasts on average 14 hours and 40 minutes. So the days are long. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
There are on average 11 hours of sunshine per day. So, the sun shines 77% of the time.
The average humidity is 56%.
The average wind speed is 16 kph (10 mph).
The average sea temperature is of 21.5 °C (71 °F). Therefore, the sea is cool for swimming.

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In July, the hottest month of the year, the weather in Syros is usually warm to hot. The average temperature is of 27.1 °C (81 °F), with a minimum of 24.7 °C (76.4 °F) and a maximum of 29.6 °C (85.2 °F).
On the coldest nights of the month, the temperature usually drops to around 21.5 °C (71 °F). However, it dropped to 20 °C (68 °F) in July 2005.
On the warmest days of the month, the temperature usually reaches around 34.5 °C (94.5 °F). However, it reached 40 °C (104 °F) in July 2017.
Precipitation amounts to only 2 mm (0.1 in), distributed over 0 days.
The day lasts on average 14 hours and 25 minutes. So the days are long.
There are on average 12 hours of sunshine per day. So, the sun shines 84% of the time.
The average humidity is 54%.
The average wind speed is 20 kph (12 mph).
The average sea temperature is of 23.5 °C (74.5 °F). Therefore, the sea can be considered barely acceptable for swimming.

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In August, the weather in Syros is usually warm to hot. The average temperature is of 27.0 °C (81 °F), with a minimum of 24.8 °C (76.6 °F) and a maximum of 29.3 °C (84.8 °F).
On the coldest nights of the month, the temperature usually drops to around 22 °C (71.5 °F). However, it dropped to 20 °C (68 °F) in August 2002.
On the warmest days of the month, the temperature usually reaches around 33.5 °C (92.5 °F). However, it reached 35 °C (95 °F) in August 1999.
Precipitation amounts to only 2 mm (0.1 in), distributed over 0 days.
The day lasts on average 13 hours and 30 minutes.
There are on average 11.5 hours of sunshine per day. So, the sun shines 85% of the time.
The average humidity is 56%.
The average wind speed is 20 kph (13 mph).
The average sea temperature is of 24 °C (75.5 °F). Therefore, the sea is warm enough for swimming.

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In September, the weather in Syros is usually warm to hot. The average temperature is of 24.1 °C (75 °F), with a minimum of 21.7 °C (71.1 °F) and a maximum of 26.4 °C (79.5 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 18 °C (64.5 °F). However, it dropped to 15 °C (59 °F) in September 2014.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 31.5 °C (88.5 °F). However, it reached 34.9 °C (94.8 °F) in September 2017.
Precipitation amounts to 12 mm (0.5 in), distributed over 2 days.
The day lasts on average 12 hours and 25 minutes.
There are on average 9.5 hours of sunshine per day. So, the sun shines 77% of the time.
The average humidity is 62%.
The average wind speed is 18 kph (11 mph).
The average sea temperature is of 23.5 °C (74 °F). Therefore, the sea can be considered barely acceptable for swimming.

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In October, the weather in Syros is usually warm. The average temperature is of 20.2 °C (68 °F), with a minimum of 18.1 °C (64.6 °F) and a maximum of 22.4 °C (72.3 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 14 °C (57 °F). However, it dropped to 11 °C (51.8 °F) in October 2011.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 27.5 °C (82 °F). However, it reached 34 °C (93.2 °F) in October 2020.
Precipitation amounts to 50 mm (2 in), distributed over 5 days.
The day lasts on average 11 hours and 10 minutes.
There are on average 7.5 hours of sunshine per day. So, the sun shines 68% of the time.
The average humidity is 68%.
The average wind speed is 19 kph (12 mph).
The average sea temperature is of 21.5 °C (70.5 °F). Therefore, the sea is cool for swimming.

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In November, the weather in Syros is usually very mild. The average temperature is of 16.6 °C (62 °F), with a minimum of 14.7 °C (58.5 °F) and a maximum of 18.6 °C (65.4 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 10 °C (50.5 °F). However, it dropped to 5 °C (41 °F) in November 2006.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 23.5 °C (74.5 °F). However, it reached 28 °C (82.4 °F) in November 2008.
Precipitation amounts to 65 mm (2.6 in), distributed over 7 days.
The day lasts on average 10 hours and 5 minutes.
There are on average 5.5 hours of sunshine per day. So, the sun shines 56% of the time.
The average humidity is 71%. Hence, the air is normally humid.
The average wind speed is 19 kph (12 mph).
The average sea temperature is of 19 °C (66 °F). Therefore, the sea is very cool for swimming.

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In December, the weather in Syros is usually mild. The average temperature is of 13.2 °C (56 °F), with a minimum of 11.4 °C (52.4 °F) and a maximum of 15 °C (59 °F).
On the coldest nights of the month, the temperature usually drops to around 6.5 °C (43.5 °F). However, it dropped to 3 °C (37.4 °F) in December 2001.
On the warmest days of the month, the temperature usually reaches around 20 °C (67.5 °F). However, it reached 23 °C (73.4 °F) in December 2010.
Precipitation amounts to 90 mm (3.5 in), distributed over 10 days.
The day lasts on average 9 hours and 35 minutes. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There are on average 3.5 hours of sunshine per day. So, the sun shines 39% of the time.
The average humidity is 72%. Hence, the air is normally humid.
The average wind speed is 21 kph (13 mph).
The average sea temperature is of 17 °C (62.5 °F). Therefore, the sea is cold for swimming.