Evvia, like the rest of Greece, revels in a warm Mediterranean climate. This weather is conducive to producing all the luscious olives and grains that Evvia is famous for.

Summer consists dry hot days, with the hottest months July and August. During this time, Evvia’s beach resorts fill with tourists and local Greeks who seek fun in the sun. However, travelers should note it is recommended during these heat waves to avoid much time outdoors in the sun during midday when the sun is especially strong. The summers however are often relieved by a system of northern breezes popularly called "meltemia". Travelers should note that while these winds are beneficial to keep cool, they often can be quite strong and disrupt the ferry schedule. The average weather during the summer ranges between 85 and 92 degrees. Throughout the year, Evvia enjoys much sunshine, estimated to be 3,000 hours per year.

During the winter the weather remains mild. The coldest time of the winter is between January and February when the temperatures are around 50 degrees. In the mountains of Euboea, there can be much snowfall. Thus, the island is popular for ski vacations as well as beach vacations, depending on the time of year. The rain season is between November and March. 

Depending on what activities travelers wish to pursue, they can choose the best time to travel. However, summer tends to be high season so for those who wish to avoid crowds should steer clear of this time period.