беабр

Осмон беабр, кабуд ва ҳаво софу серун буд.
The sky was cloudless, blue and the weather was clear and mild.
Обу ҳавои абрноку серборон дар зимистон, обу ҳавои хушку беабр дар тобистон бештар аст.
Mostly the weather is cloudy and rainy in winter, and the weather is dry and cloudless in summer.

Bonus:
Opposite: абрнок (cloudy)

The prefix бе means without. The translations of many Tajik words beginning with бе end with less in English.
бешубҳа: doubtless
беҳисоб: countless
бедил: heartless
бемӯй: hairless
беқонун: lawless
беранг: colourless