noun
under the blazing sun; in sweltering heat
Refers to being outdoors in extremely hot, sunny weather. Often used with verbs like 歩く, 待つ, 作業する.
炎天下で長時間待たされた。
I was made to wait for a long time under the blazing sun.
炎天下の作業は熱中症に注意
When working in sweltering heat, you need to be careful of heatstroke.