Precipitation standards are as below.
| time precipitation(mm) | recent rain condition |
|---|---|
| under 1mm | no rainfall |
| 1mm-3mm | light rain |
| 3mm-10mm | rain |
| 10mm-20mm | strong rain |
| 20mm-30mm | hard rain |
| 30mm-50mm | heavy rain |
| 50mm-80mm | pouring rain |
| over 80mm | driving rain |
| e | error |
