Whenever I have seen Venus described, its high surface temperature is attributed to an intense greenhouse effect. This seems to make sense, as its atmosphere is roughly 96% CO2. But on Earth, the greenhouse effect works because the atmosphere is (mostly) transparent to sunlight, but (somewhat) opaque to longer wavelength light radiated back from the surface.
The atmosphere of Venus would be very opaque to longer wavelength light from the surface, just like Earth (at least around the CO2 absorption bands). But isn't Venus also very cloudy and largely opaque to visible light? If the solar radiation that reaches the surface is limited, wouldn't this also limit the ability of the CO2 to "trap" heat?
The atmospheric pressure at the surface of Venus is much higher than it is at the surface of Earth. Isn't this a more straight-forward explanation for much of the high temperature?