The term for "多云" in English can be transliterated as "duoyu," but to convey the general concept of a sky with numerous clouds without emphasizing specific terms, one could simply say "Partially cloudy" or "Overcast."
Additionally, for a more idiomatic expression, "多云" might be articulated as "overcast," or if employing a more explanatory approach, "cloudy with scattered sunshine."

Overcast

多云在英語中用"partly cloudy"來表達(dá)。

多云英語是overcast