Weather: similar to Mallorca

Temperatures in central (eastern) Pelion range between 23 and 38 degrees from May to October, in high summer they are around 32 degrees, higher temperatures are the exception. At night there is always a cooling down wind from the mountains, in the morning an up wind from the sea. 

Even in July/August, you rarely switch on the air conditioning. And when it really gets hot, you go up into the mountains.
Central Pelion is extremely forested. Therefore, even in summer, there are one or two thunderstorm days during a three-week stay. In May /June or September / October it can also rain for two or three days. The water varies between 22 degrees in May and 26 degrees in August. You can swim comfortably until November.

In southern Pelion, temperatures are more like in the rest of Greece, so it can get quite hot in summer. But in the peripheral months, April / May and September / October, the weather is more comfortable than in central Pelion.