Dog Days - The Dates

The Dates

In Ancient Rome, the Dog Days ran from July 24th through August 24th, or, alternatively, from July 23 through August 23rd. In many European cultures (German, French, Italian) this period is still said to be the time of the Dog Days.

The Old Farmer's Almanac lists the traditional period of the Dog Days as the 40 days beginning July 3rd and ending August 11th, coinciding with the ancient heliacal (at sunrise) rising of the Dog Star, Sirius. These are the days of the year with the least rainfall in the Northern Hemisphere.

According to the 1552 edition of the The Book of Common Prayer, the "Dog Daies" begin July 6th and end August 17th. But this edition, the 2nd book of Edward VI, was never used extensively nor adopted by the Convocation of the Church of England. The lectionary of 1559 edition of the Book of Common Prayer indicates: "Naonae. Dog days begin" with the readings for July 7th and end August 18th. But this is noted as a misprint and the readings for September 5th indicate: "Naonae. Dog days end". This corresponds very closely to the lectionary of the 1611 edition of the King James Bible (also called the Authorized version of the Bible) which indicates the Dog Days beginning on July 6th and ending on September 5th. A recent reprint of the 1662 edition of the Book of Common Prayer contains no reference to the Dog Days.

Please note: Due to introduction of the modern Gregorian Calendar, 11 days must be added to each of the 16th and 17th Century dates referenced above for them to correlate correctly with modern-day dates as concerns astronomical observations and climate. First adopted by Southern European Catholic countries in the 16th Century, the Gregorian Calendar was not used in England or its New World colonies until 1752. This modern calendar accurately calculates the astronomical length of one year (the exact time it takes the earth to orbit the sun) to be 365.2425 days. This corrected the approximated 365 and 1/4 day year length of the previously used Julian Calendar introduced in 46 B.C. Because the length of each Julian Calendar year was 11 minutes 48 seconds too long, over the centuries, seasonal changes gradually occurred on earlier and earlier dates. The Gregorian Calendar uses a formula to reduce from 100 to 97 the number of leap years (extra days) in a 400-year period thus cutting the average calculated length of a year to its actual duration. By 1752 when the Gregorian Calendar was adopted by England, the Julian Calendar had fallen behind by 11 days total since 46 B.C. Upon implementation of the Gregorian Calendar, those days were added back by jumping overnight from September 2nd to September 14th, 1752, thus catching the calendar up with the seasons.

The Book of Common Prayer would have provided the official liturgical calendar for Jamestown, Virginia, from 1607 so it may be assumed that the Dogs Days likely have been known in the New World at least since that time.