January | February | March | April | May | June | July | August | September | October | November | December
| 1 | 3.1 | 3.1 | 3.0 | 2.6 | 2.1 | 1.6 | 1.3 | 1.1 | 1.2 | 1.5 | 1.9 | 2.3 | 2.5 | 2.7 | 2.6 | 2.4 | 2.1 | 1.8 | 1.5 | 1.4 | 1.4 | 1.7 | 2.1 | 2.5 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2 | 2.8 | 2.9 | 2.9 | 2.7 | 2.3 | 1.9 | 1.6 | 1.3 | 1.3 | 1.4 | 1.7 | 2.0 | 2.3 | 2.5 | 2.5 | 2.5 | 2.3 | 2.0 | 1.7 | 1.6 | 1.5 | 1.7 | 1.9 | 2.2 |
| 3 | 2.5 | 2.7 | 2.8 | 2.7 | 2.5 | 2.2 | 1.8 | 1.6 | 1.4 | 1.5 | 1.6 | 1.8 | 2.1 | 2.3 | 2.4 | 2.4 | 2.3 | 2.2 | 2.0 | 1.8 | 1.7 | 1.7 | 1.8 | 2.0 |
| 4 | 2.3 | 2.4 | 2.6 | 2.6 | 2.5 | 2.3 | 2.1 | 1.9 | 1.7 | 1.6 | 1.6 | 1.7 | 1.9 | 2.1 | 2.2 | 2.3 | 2.3 | 2.3 | 2.2 | 2.1 | 2.0 | 1.9 | 1.9 | 1.9 |
| 5 | 2.0 | 2.2 | 2.3 | 2.4 | 2.4 | 2.4 | 2.3 | 2.1 | 1.9 | 1.8 | 1.7 | 1.7 | 1.7 | 1.8 | 2.0 | 2.1 | 2.2 | 2.3 | 2.4 | 2.3 | 2.2 | 2.1 | 2.0 | 1.9 |
| 6 | 1.9 | 1.9 | 2.0 | 2.2 | 2.3 | 2.4 | 2.4 | 2.3 | 2.2 | 2.0 | 1.8 | 1.7 | 1.6 | 1.6 | 1.8 | 1.9 | 2.1 | 2.3 | 2.4 | 2.5 | 2.5 | 2.3 | 2.2 | 2.0 |
| 7 | 1.8 | 1.7 | 1.8 | 1.9 | 2.1 | 2.3 | 2.4 | 2.5 | 2.4 | 2.3 | 2.0 | 1.8 | 1.6 | 1.5 | 1.5 | 1.7 | 1.9 | 2.2 | 2.3 | 2.6 | 2.7 | 2.6 | 2.4 | 2.1 |
| 8 | 1.9 | 1.6 | 1.5 | 1.6 | 1.8 | 2.0 | 2.3 | 2.5 | 2.6 | 2.5 | 2.3 | 2.0 | 1.7 | 1.5 | 1.4 | 1.4 | 1.7 | 2.0 | 2.3 | 2.6 | 2.8 | 2.9 | 2.7 | 2.4 |
| 9 | 2.0 | 1.6 | 1.4 | 1.3 | 1.5 | 1.8 | 2.1 | 2.4 | 2.6 | 2.7 | 2.5 | 2.3 | 1.9 | 1.5 | 1.3 | 1.2 | 1.4 | 1.7 | 2.1 | 2.6 | 2.9 | 3.0 | 3.0 | 2.7 |
| 10 | 2.3 | 1.8 | 1.4 | 1.2 | 1.2 | 1.5 | 1.9 | 2.3 | 2.6 | 2.8 | 2.7 | 2.5 | 2.1 | 1.7 | 1.3 | 1.1 | 1.2 | 1.4 | 1.9 | 2.4 | 2.8 | 3.1 | 3.1 | 3.0 |
| 11 | 2.6 | 2.0 | 1.5 | 1.1 | 1.0 | 1.1 | 1.5 | 2.0 | 2.4 | 2.8 | 2.9 | 2.7 | 2.4 | 2.0 | 1.5 | 1.1 | 1.0 | 1.2 | 1.5 | 2.1 | 2.6 | 3.0 | 3.3 | 3.2 |
| 12 | 2.9 | 2.4 | 1.8 | 1.2 | 0.9 | 0.9 | 1.2 | 1.7 | 2.2 | 2.6 | 2.9 | 2.9 | 2.7 | 2.3 | 1.8 | 1.3 | 1.0 | 1.0 | 1.2 | 1.7 | 2.3 | 2.9 | 3.2 | 3.3 |
| 13 | 3.1 | 2.7 | 2.1 | 1.5 | 1.0 | 0.8 | 0.9 | 1.3 | 1.9 | 2.4 | 2.8 | 2.9 | 2.9 | 2.5 | 2.1 | 1.6 | 1.2 | 1.0 | 1.0 | 1.4 | 2.0 | 2.6 | 3.1 | 3.3 |
| 14 | 3.3 | 3.0 | 2.5 | 1.9 | 1.3 | 0.9 | 0.8 | 1.0 | 1.5 | 2.0 | 2.5 | 2.9 | 2.9 | 2.8 | 2.4 | 1.9 | 1.4 | 1.1 | 1.0 | 1.2 | 1.6 | 2.2 | 2.7 | 3.2 |
| 15 | 3.4 | 3.2 | 2.8 | 2.3 | 1.6 | 1.1 | 0.9 | 0.9 | 1.2 | 1.7 | 2.2 | 2.6 | 2.9 | 2.9 | 2.6 | 2.2 | 1.8 | 1.3 | 1.1 | 1.1 | 1.4 | 1.8 | 2.4 | 2.9 |
| 16 | 3.2 | 3.3 | 3.1 | 2.6 | 2.1 | 1.5 | 1.1 | 0.9 | 1.0 | 1.4 | 1.8 | 2.3 | 2.6 | 2.8 | 2.8 | 2.5 | 2.1 | 1.7 | 1.4 | 1.2 | 1.3 | 1.6 | 2.0 | 2.5 |
| 17 | 2.9 | 3.1 | 3.1 | 2.9 | 2.4 | 1.9 | 1.4 | 1.1 | 1.0 | 1.2 | 1.5 | 1.9 | 2.3 | 2.6 | 2.7 | 2.6 | 2.4 | 2.1 | 1.7 | 1.4 | 1.3 | 1.5 | 1.7 | 2.1 |
| 18 | 2.5 | 2.8 | 3.0 | 2.9 | 2.7 | 2.3 | 1.8 | 1.4 | 1.2 | 1.2 | 1.3 | 1.6 | 2.0 | 2.3 | 2.5 | 2.6 | 2.6 | 2.4 | 2.1 | 1.8 | 1.6 | 1.5 | 1.6 | 1.8 |
| 19 | 2.1 | 2.4 | 2.7 | 2.8 | 2.7 | 2.5 | 2.2 | 1.9 | 1.5 | 1.3 | 1.3 | 1.4 | 1.6 | 1.9 | 2.2 | 2.5 | 2.6 | 2.5 | 2.4 | 2.2 | 1.9 | 1.7 | 1.6 | 1.6 |
| 20 | 1.8 | 2.0 | 2.3 | 2.5 | 2.6 | 2.6 | 2.5 | 2.2 | 1.9 | 1.6 | 1.4 | 1.3 | 1.4 | 1.6 | 1.9 | 2.2 | 2.4 | 2.6 | 2.6 | 2.5 | 2.3 | 2.0 | 1.8 | 1.6 |
| 21 | 1.6 | 1.7 | 1.9 | 2.1 | 2.4 | 2.5 | 2.6 | 2.5 | 2.3 | 2.0 | 1.7 | 1.4 | 1.3 | 1.3 | 1.5 | 1.8 | 2.1 | 2.5 | 2.7 | 2.7 | 2.7 | 2.5 | 2.1 | 1.8 |
| 22 | 1.5 | 1.4 | 1.5 | 1.7 | 1.9 | 2.3 | 2.5 | 2.6 | 2.6 | 2.4 | 2.1 | 1.7 | 1.4 | 1.2 | 1.2 | 1.4 | 1.8 | 2.2 | 2.5 | 2.8 | 2.9 | 2.8 | 2.5 | 2.2 |
| 23 | 1.7 | 1.4 | 1.2 | 1.3 | 1.5 | 1.9 | 2.2 | 2.5 | 2.7 | 2.6 | 2.4 | 2.1 | 1.7 | 1.3 | 1.1 | 1.1 | 1.4 | 1.8 | 2.3 | 2.7 | 3.0 | 3.0 | 2.9 | 2.6 |
| 24 | 2.1 | 1.6 | 1.2 | 1.0 | 1.1 | 1.4 | 1.9 | 2.3 | 2.6 | 2.8 | 2.7 | 2.4 | 2.0 | 1.6 | 1.2 | 1.0 | 1.1 | 1.4 | 1.9 | 2.4 | 2.9 | 3.1 | 3.1 | 2.9 |
| 25 | 2.5 | 1.9 | 1.4 | 1.0 | 0.9 | 1.0 | 1.4 | 1.9 | 2.4 | 2.7 | 2.8 | 2.7 | 2.4 | 1.9 | 1.4 | 1.1 | 1.0 | 1.1 | 1.5 | 2.0 | 2.6 | 3.0 | 3.2 | 3.2 |
| 26 | 2.8 | 2.3 | 1.7 | 1.2 | 0.8 | 0.8 | 1.1 | 1.5 | 2.1 | 2.5 | 2.8 | 2.8 | 2.6 | 2.2 | 1.8 | 1.3 | 1.0 | 1.0 | 1.2 | 1.6 | 2.2 | 2.8 | 3.2 | 3.3 |
| 27 | 3.1 | 2.6 | 2.1 | 1.5 | 1.0 | 0.8 | 0.9 | 1.2 | 1.7 | 2.2 | 2.6 | 2.8 | 2.8 | 2.5 | 2.1 | 1.6 | 1.2 | 1.0 | 1.0 | 1.4 | 1.9 | 2.4 | 2.9 | 3.2 |
| 28 | 3.2 | 2.9 | 2.4 | 1.8 | 1.2 | 0.9 | 0.8 | 1.0 | 1.4 | 1.9 | 2.4 | 2.7 | 2.8 | 2.7 | 2.3 | 1.9 | 1.4 | 1.1 | 1.0 | 1.2 | 1.6 | 2.1 | 2.6 | 3.0 |
| 29 | 3.2 | 3.1 | 2.7 | 2.2 | 1.6 | 1.1 | 0.9 | 0.9 | 1.2 | 1.6 | 2.1 | 2.5 | 2.7 | 2.7 | 2.5 | 2.1 | 1.7 | 1.3 | 1.1 | 1.1 | 1.4 | 1.8 | 2.3 | 2.8 |
| 30 | 3.1 | 3.1 | 2.9 | 2.4 | 1.9 | 1.4 | 1.0 | 0.9 | 1.1 | 1.4 | 1.9 | 2.3 | 2.6 | 2.7 | 2.6 | 2.3 | 2.0 | 1.6 | 1.3 | 1.2 | 1.3 | 1.6 | 2.1 | 2.5 |
| 31 | 2.9 | 3.0 | 2.9 | 2.6 | 2.2 | 1.7 | 1.3 | 1.1 | 1.1 | 1.3 | 1.7 | 2.1 | 2.4 | 2.6 | 2.6 | 2.5 | 2.2 | 1.8 | 1.5 | 1.3 | 1.3 | 1.5 | 1.9 | 2.3 |
Source: Hydrographic Department, Royal Thai Navy