m sorry to inform you that the overall (net) radiative effect of clouds on the global surface of the Earth is not one of warming, but one of cooling. Net CRE globally is -00 W/m^0 according to CERES, which is quite significant. The point is this: Yes, clouds (and atmospheric conditions typically associated with clouds) reduce surface cooling rates during the night. But they ALSO reduce surface heating rates during the day. And the latter effect is evidently much stronger overall than the former.