The Public Power Corporation (PPC) reported that several parts of the capital had suffered blackouts due to the huge surge in electricity consumption.
The worst affected areas included densely-populated central neighborhoods such as Kypseli and Pangrati where the heat was most intense, rising to temperatures above 40 degrees Celsius (104 Fahrenheit). The situation is expected to worsen on Monday when the heatwave is forecast to peak, reaching up to 42C (107.6F) in some parts of the capital.
The high temperatures, combined with winds of up to 8 on the Beaufort scale in some areas, also kept the fire service busy.
In Attica there were blazes in Papagou, north of Athens, in Keratea in the southeast, and in Pikermi and on the slopes of Mount Hymettus, both east of Athens.
One of the largest blazes this weekend broke out on Saturday in Thessaloniki’s Seikh-Sou Forest, apparently from a discarded lit cigarette. Dozens of firefighters were dispatched to the urban forest and had managed to bring the blaze under control by the early afternoon. Firemen remained on standby to extinguish a possible rekindling of the embers.
Wildfires were also reported on the southern Aegean island of Crete, in the area of Arkalochori, near the port of Iraklio, and near Kattavia, on the southern tip of Rhodes.
The fire service and regional authorities have been instructed to remain on alert on Monday when temperatures are expected to peak and the risk of forest fires will be even more pronounced, particularly in dry areas.