Climatic Zones: Most areas of Greece are dominated by Mediterranean climate while northern Greece belongs to temperate continental climate.

Temperature: The whole year of Greece can be divided into four distinct seasons according to the temperature difference. It has sunny and hot summer and rainy and cold winter; in spring and autumn, it is mild. The average annual temperature of Greece is 11-22℃ (51.8-71.6℉).  

Precipitation: The average annual precipitation of Greece is 289mm (11.4in), and the rainfall concentrates in winter rather than summer, which is an obvious feature of Mediterranean climate. In the western region, the mean annual precipitation is about 900-1,200mm, far more than that in the eastern region, which is 400-700mm.

Warmest Month: July: 21-34℃ (69.8-93.2℉)

Coolest Month: January: 3-12℃ (37.4-53.6℉)

April to June is the best time to have a visit in Greece for several reasons:

Sunny day: In this season, it is sunny almost every day but not so dry or hot. You will not be troubled by rainfall during your tour and thus have a delighted visit. 

Adequate supplies: Most business for tourists restart at that time, providing adequate foods and accommodations and making the islands vivifying.

Loose flow of tourists: April to June is the shoulder season for traveling in Greece when there are not many customers. You can slow down to fully explore and enjoy each attraction. 

Actually, it has the same weather condition as April to June from September to October, which is suitable for outdoor tours too. You can choose between the two periods according to your time.

Spring: March to April

Temperature: 6-20℃ (42.8-68℉)
Rainfall: 77mm (3.0in)
Clothes to Wear: thin sweater, trench coat, jacket, jeans, sweat pants, sneakers
Weather: 
It is mild in spring in Greece. It gradually warms up but cannot be as hot as the weather in summer. In March, it is often windy; in April, it is always warm and sometimes rainy. Occasionally, Greece may be attacked by sandstorm from Sahara desert in spring.
Travel Recommendation:
In spring, you can have a tour of Greece to enjoy its history. In Athens, you can go to visit Acropolis and Syntagma Square, shop in the Monastirak Square, and learn wonderful mythological stories about ancient Greece. In Olympia, you can have a tour of the archaeological site to recall the origin of Olympic Games. Easter is the most important religious celebration in Greece. In 2025, Greek will celebrate this festival on April 20. On the Easter, people will dress up in all kinds of strange clothes and dance with music on the streets. The party will go on until late at night, and you can join in them to feel their happiness and excitement. If you plan to travel to Greece in spring of 2025, do not miss the amazing activities of Easter. 

Summer: May to September

Temperature: 13-34℃ (55.4-93.2℉)
Rainfall: 106mm (4.2in)
Clothes to Wear: shirts, skirts, light pants, thin jacket, bikini
Weather: 
Summer is the longest and hottest season in Greece when the temperatures are usually above 30℃ (86℉) and sometimes can reach 40℃ (104℉). In this season, it is sunny almost every day and there is less rainfall. It has the most sunlight among the four seasons, making the sea temperature climb to 24-25℃ (75.2-77℃), which is suitable for water activities.
Travel Recommendation:
If you are water sports fans, traveling to Mediterranean coast or Mediterranean islands like Santorini, Crete, and Mikonos in this season is a good choice. When feeling tired, you can also bask in the sun in a bikini and enjoy yourself on the beach. 

Tips:

1. July to August is the tourist high season in Greece. At that time, the air tickets and attraction tickets will be more expensive than usual, and the attractions will be full of tourists. 
2. Please pay attention to the hot climate of Greece. You can stay indoors to avoid sunstroke until around 5pm when it gets not too hot. You do not have to worry about time because the sun goes down at almost 9pm. 
3. Protection items from the sun are needed to avoid getting sunburned.

Autumn: October to November

Temperature: 10-23℃ (50-73.4℉)
Rainfall: 102mm (4.0in)
Clothes to Wear: shirts, light pants, trench coat
Weather:
Greece’ autumn, a transition between summer and winter is relatively short. Entering September, it gradually gets cool with many sunny days. From October to November, a large temperature difference between morning and evening appears. Precipitation begins to increase and there are less sunny days. Windy days are also increasing.
Travel Recommendation: 
After a long and hot summer, the arrival of autumn allows more people to engage in outdoor activities without hesitation. It’s a good choice to visit these historical heritages in Athens and Olympia. In addition to visiting the islands, mountain climbing is especially popular in autumn in Greece. You can climb to the “Castle in the Sky” in Meteora to view towering rocks. Besides, you can challenge yourself with authentic rock climbing.

Winter: December to February

Temperature: 3-13℃ (37.4-55.4℃)
Rainfall: 153mm (6.0in)
Clothes to Wear: sweater, winter jacket, thick pants
Weather:
Winter is the coldest season in Greece, with the lowest temperature of 3℃ (37.4℉). In this season, rainfall is gradually increasing. The total amount of precipitation in winter is 165mm and in the three months, 31 days are rainy on average. In December, the rainfall can be over 60mm on average, making the humidity rise up to the highest of the year. In northern Greece where it is colder, it can be snowy in winter. 
Travel Recommendation:
In winter, traveling to Nea Kameni is a good choice, where you can get an up-close view of the active volcano. On neighboring Palea Kameni, you can also experience hot springs to relieve physical and mental stress.
Besides, there are some ski slopes in the northern snowy areas. Those are all natural snow resorts, so even if you fall, it won’t hurt so much. If you love skiing, you will enjoy yourself there.

Tips:

1. Winter is the tourist slack season. Most restaurants, hotels and other serve places for tourists are closed, but the air tickets and attraction tickets will be at half the usual price.
2. Raingear should be carried with you because winters of Greece are often rainy.