dog day
/ˈdɒɡ deɪ/noun
1In plural The hottest part of the summer, associated in ancient times with the heliacal rising of the Dog Star in the Mediterranean area, and formerly considered to be the most unhealthy period of the year and a time of ill omen.
- The dog days have been variously reckoned, as depending on either the Greater Dog Star (Sirius) or the Lesser Dog Star (Procyon), and on either the heliacal rising or the cosmical rising (which occurs at an earlier date). The timing of these risings depends on latitude, and they do not occur at all in most of southern hemisphere; in addition, owing to the precession of the equinox they now take place later in the year. As a result very different dates have been assigned for the dog days, their beginning ranging from 3 July to 15 August, and their duration varying from 30 to 61 days. In the Calendar of the 1552 Book of Common Prayer they run from 7 July to 5 September. In current calendars they are often said to begin on 3 July and end on 11 August (i.e. the 40 days preceding the cosmical rising of Sirius at the latitude of Greenwich).The name arose from the pernicious qualities of the season being attributed to the ‘influence’ of the Dog Star; but it has long been popularly associated with the belief that at this season dogs are most liable to go mad..
2A day in the dog days.
3 Figurative. In plural In early use: an evil time; a period in which malignant influences prevail. Now: a period of inactivity or decline.
Origin
Mid 16th century; earliest use found in Thomas Elyot (c1490–1546), humanist and diplomat. From dog + day, after post-classical Latin caniculares dies dog days, itself after Hellenistic Greek κυνάδες ἡμέραι.