occurrence

六月下雪在这里是极其罕见的事情。

Snow in June is an extremely rare ___occurrence here.

暴风雨期间，停电是常有的事。

Power outages were a frequent ___occurrence during the storm.

研究人员正在研究极端天气事件增多的现象。

Researchers are studying the increased ___occurrence of extreme weather events.