Meteorologist Nikola Ziakopoulou forecasts a significant drop in temperatures across Greece this weekend, starting with northern regions on Saturday and extending nationwide by Sunday. Brief thunderstorms are expected in the northeastern Aegean along with snowfall in northern mountainous areas. While Sunday will be windy and cold, it will see clearer skies in many regions. The overview includes potential light rain for Attica and much sunshine in Thessaloniki, with temperatures ranging from 5 to 23 degrees Celsius.