| W | Weather during past hour |
| W1 | Past weather |
| W2 |
| Code figure | |
|---|---|
| 0 | Cloud covering 1/2 or less of the sky throughout the appropriate period |
| 1 | Cloud covering more than 1/2 of the sky during part of the appropriate period and covering 1/2 or less during part of the period |
| 2 | Cloud covering more than 1/2 of the sky throughout the appropriate period |
| 3 | Sandstorm, duststorm or blowing snow |
| 4 | Fog or ice fog or thick haze |
| 5 | Drizzle |
| 6 | Rain |
| 7 | Snow, or rain and snow mixed |
| 8 | Shower(s) |
| 9 | Thunderstorm(s) with or without precipitation |