Table 2. Meteorological conditions that define the Pasquill stability classes

Wind speed (m/s)	Daytimea (AM 6-PM 7)			Nighttimeb (PM 7-AM 6)
	Strong	Moderate	Weak	> 3/10	≤ 3/10
< 2	Ac	A-B	B	F	G
2-3	A-B	B	C	E	F
3-5	B	B-C	C	D	E
5-6	C	C-D	D	D	D
> 6	C	D	D	D	D

Amount of insolation
Cloudiness
A-very unstable, B-unstable, C-sightly unstable, D-neutral, E-sightly stable, F-stable