This is the 12315th most frequent Russian word.
июньское
"Июньское" means "June's" or "related to June."
In this sentence, 'июньское' (June) is an adjective modifying 'солнце' (sun), indicating that the sun is specific to the month of June.
Июньское солнце ярко освещает землю.
The June sun brightly illuminates the ground.
Here, 'июньское' (June) serves as an adjective describing 'утро' (morning), highlighting the period of time as a characteristic of the morning.
Июньское утро было тихим и свежим.
The June morning was quiet and fresh.
In this example, 'июньским' is the instrumental adjective form of 'июньское', modifying 'ветром' (wind), which refers to the wind associated with June since the sentence uses an instrumental case.