Dog days Dog days The dog days or are the hot, sultry days of summer. They were historically the period following the heliacal rising of the star system Sirius, which Greek and Roman astrology connected with heat, drought, sudden thunderstorms, lethargy, fever, mad dogs, and bad luck. They are now taken to be the hottest, most uncomfortable part of summer in the Northern Hemisphere. The English name is a calque of the Latin "" (."the puppy days"), itself a calque of the Greek "kynádes hēmérai" (, "dog days"). The Greeks knew the star α Canis Majoris by several names, including Sirius (,
Sirius hemispheres. Just as the appearance of Sirius in the morning sky marked summer in Greece, it marked the onset of winter for the Māori, whose name "Takurua" described both the star and the season. Its culmination at the winter solstice was marked by celebration in Hawaii, where it was known as "Ka'ulua", "Queen of Heaven". Many other Polynesian names have been recorded, including "Tau-ua" in the Marquesas Islands, "Rehua" in New Zealand, and "Ta'urua-fau-papa" "Festivity of original high chiefs" and "Ta'urua-e-hiti-i-te-tara-te-feiai" "Festivity who rises with prayers and religious ceremonies" in Tahiti. The Hawaiian people had many names for Sirius, including