When it hits
Day 38 at 08:00 on the 
Wage Slave's run
No warning comes first.
Starts with Continuous Rain, ends with 
Rain Clears.
The same on every run: Student, Warehouse Manager
What comes
No zombies: this crisis is about the weather, sickness or pests, not a siege.
From the game files1
Crisis 108
| id | 108 |
|---|---|
| CrisisID | 108 |
| StartEvent | [40665] |
| EndEvent | [40666] |
| Des | Crisis_Des_201 |
| Des_Local | 阴雨 |