How can one tell the difference between opaque, translucent and transparent clouds?
These categories are somewhat qualitative. We ask for your best judgement. The distinction is easiest to explain for an overcast day. If you cannot even tell where the Sun is, you have opaque clouds. If you can see the Sun but it is just a brighter spot that does not hurt your eyes, you have translucent clouds. If the Sun can be seen as a bright circle you have transparent clouds. On non-overcast days, if the Sun is not between you and the clouds, you can look for grey shadows at the cloud base (opaque), or blue sky visible through the cloud (transparent).
