estival       
adjective  formal uk/ˈiː.stɪ.vəl/ us/ˈes.tɪ.vəl/ /ˈes.tɪ.vəl/ /ˈiː.stɪ.vəl / (UK also aestival)
 夏季的,夏天的
relating to or typical of summer
  We chose the estival menu with seasonal fruits and vegetables. 我们选择了提供时令水果蔬菜的夏季菜单。 
 - More examples
- The day had an estival feel to it.
- The estival heat was unbearable.
- He indicated that in the course of the aestival recess he might be reconsidering the terms and conditions of my employment.