A clear hour
The faint stars stay faint
On a transparent night the air itself is the limit. Low cloud, haze and a damp ground take the faint ones first.
Clarity forecast
Transparency
See through the air.
What transparency is
A milky hour
Not all of it looks like weather
Smoke, dust and a sheet of thin high cloud can leave the sky looking empty of rain, and still soften every star in it.
See through the air, and find what is softening the stars.