We have no meanings for "partly overcast" in our records yet.
1 The moon wasn't up yet, and it was partly overcast and very dark.
2 The sky was partly overcast with clouds offering lovely breadths of light and shade.
3 The sea was a study in textures, as the sky was partly overcast and getting on toward evening.
4 I disembarked into a cool, partly overcast afternoon, found transportation almost immediately, and set out for Dave's office address.
5 August 23 arrived: calm, partly overcast , and -43.6ºF.
6 August 23 arrived: calm, partly overcast , and -43.6deg.F.
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