The short answer
In Attica an unheated pool is pleasant roughly from late May to early October. On the southern coast and in the centre a little earlier, in the higher north a little later. With a heat pump and a cover, the season stretches from spring to autumn.
Differences from area to area
Central Athens, Piraeus and the southern suburbs are the warmest areas, with mild winters. The northern suburbs, Penteli and especially Dionysos, Varnavas and Vilia are cooler because of altitude. The east coast is cooled by the meltemi. These differences can shift the start of the season by a few weeks.
Sun and position
A pool that gets sun from morning to afternoon warms much faster. A pool in the shadow of the house or under trees can stay cold until July. That is why position is the first topic at the site visit.
Wind and evaporation
Wind cools water because it increases evaporation. In Rafina or Artemida, a week of meltemi can lower the temperature noticeably. A planted fence or a wall on the north side protects it. See the page on Rafina and Marathon.
How much longer the season gets with heating
A correctly sized heat pump, together with a night cover, brings the season forward by several weeks and extends it by several weeks. For families with small children, who get cold quickly, the difference is big. See the plant room.
Heatwaves
In July and August heatwaves, the water in a small pool can get too warm. Chlorine demand goes up and algae get their chance. The pump runs longer, you check chlorine more often and, if your heat pump has a cooling mode, it can bring the temperature down a little.
From our experienceMost of our Attica clients who added a heat pump after a season without one tell us they should have fitted it from the start.
