also: うき
noun
signs of rain; threatening to rain
Describes the look or feel of impending rain, such as dark clouds or a damp atmosphere. Often used in weather descriptions.
空に雨気が漂っている。
There is a sign of rain in the air.
雨気を含んだ風が吹いてきた。
A wind carrying the threat of rain began to blow.
雨模様 also means 'signs of rain' or 'threatening to rain', but is more common and can refer to the appearance of the sky or the weather forecast. 雨気 is less frequent and more literary.
雨催い is a synonym meaning 'threatening to rain', often used in a similar way. 雨気 is slightly more concise and may feel more classical.
Compound of 雨 (あめ, 'rain') and 気 (け, 'sign, feeling'). The reading あまけ is a common rendaku form of あめ + け. The alternate reading うき uses the on'yomi of both characters and is less common.