Like low-level clouds, mid-level couds such as altocumulus and altostratus can show intense colors during sunrise or sunset. The coloring occurs typically 5 to 10 minutes after sunset (or before sunrise), at the time the sun is setting as seen from the base of the cloud layer. A really spectacular cloud coloring of altocumulus is not very common, because the sky is usually a bit hazy either below the cloud in the boundary layer near you, or hundreds of miles further where the sun is setting. The sky should be very clear yet have the right dust content to make the hues deeper red and orange.
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