The month by the Moon.

The Moon has no light of its own; what you see is sunlight on the half turned toward the Sun. As the Moon orbits, the lit part you can see grows from new to full and shrinks back, a rhythm of about 29 and a half days.

New moons are for beginnings, full moons for what comes to light. Between them the calendar marks the two quarters, when the Moon is exactly half lit.

The Moon moves quickly, spending about two and a half days in each zodiac sign before crossing into the next. The sign it is in colours the mood of the day for many people.

When the Moon has made its last aspect before changing sign, it is called void of course: an old idea that plans made then tend to fizzle, so it is treated as a good time to rest rather than launch.