It is time to depart, but the clouds are ominous so we are on standby.
It is time to depart, but the weather isn't looking good so we are on standby.
「出発する時間になったけど、雲行きが怪しいから待機です」= It is time to depart, but the clouds are ominous so we are on standby.
「出発する時間になった」= It is time to leave / It is time to depart
「出発する」= to depart; to leave
「雲行きが怪しい」= the clouds are ominous (= 「天気が悪そうに見える」= the weather isn't looking good / the weather is looking bad )
「待機です」 = on standby
になります。
ご参考までに。