Buck Moon

Male deer shed and regrow their antlers every year, and by July the new growth is well underway, still sheathed in the soft vascular skin called velvet. It is among the fastest tissue growth rates in the animal kingdom — a white-tailed buck adds roughly half a centimetre a day at peak, and the largest deer do considerably better: bull elk and moose can put on well over two centimetres a day.

Thunder Moon records the reliability of July storms. Wort Moon is the Old English name, “wort” being the general term for a useful herb; July was when medicinal plants were gathered and dried. Hay Moon marks the first cut.

July is also when Earth reaches aphelion, its greatest distance from the sun. This has nothing to do with the moon, but it is a useful reminder that seasons are caused by axial tilt rather than distance: the northern hemisphere is at its hottest at precisely the moment the whole planet is furthest from the sun.

Also known as

• Thunder Moon
• Hay Moon
• Wort Moon

The 1778 record

Travelling among the Dakota in 1766 and 1767, Captain Jonathan Carver wrote down all twelve month names in a single passage. Published in 1778, it predates the almanac list by roughly a century and a half and is the oldest independent check on these names.