- SECTION 0
| iii | iRixhVV |
| Nddff | 1snTTT | 2snTdTdTd | 4PPPP | 5appp | 6RRRtR | 7wwW1W2 | 8NhCLCMCH |
| 333 | 1snTxTxTx (at 1800 UTC) | 2snTnTnTn (at 0600 UTC) | 3EsnTgTg (at 0600 UTC) | 4E'sss (at 0600 UTC) | 8NsChshs | 9SpSpspsp |
| 555 | 1V'f'/V'f''f'' | 2snTwTwTw | iiirrr |
Interpretation
| iii | Station Number |
| iRixhVV | |
| iR | Inclusion or omission of precipitation data |
| ix | Inclusion or omission of weather group |
| h | Height of base of lowest cloud |
| VV | Horizontal visibility |
| Nddff | |
| N | Total Cloud amount |
| dd | Wind direction in tens of degrees |
| ff | Wind speed in knots |
| 1snTTT | |
| 1 | Indicator |
| sn | Sign of temperature |
| TTT | Dry-bulb temperature in tenths of a degree Celsius |
| 2snTdTdTd | |
| 2 | Indicator |
| sn | Sign of temperature |
| TdTdTd | Dew-point temperature in tenths of a degree Celsius |
| 4PPPP | |
| 4 | Indicator |
| PPPP | Last four figs. of air pressure (reduced to mean sea level) in millibars and tenths |
| 5appp | |
| 5 | Indicator |
| a | Characteristic of pressure change |
| ppp | Pressure change over last three hours in millibars and tenths |
| 6RRRtR | |
| 6 | Indicator |
| RRR | Amount of rainfall |
| tR | Duration of period of RRR in units of six hours. Main hours only, so at 0001 and 1200 UTC tR=1 At 0600 and 1800 tR=2 |
| 7wwW1W2 | |
| 7 | Indicator |
| ww | Present weather, manned station |
| W1W2 | Past weather, manned station |
| 8NhCLCMCH | |
| 8 | Indicator |
| Nh | Amount of low cloud, or medium cloud if no low cloud present |
| CL | Form of low cloud |
| CM | Form of medium cloud |
| CH | Form of high cloud |
| 333 | Regional Indicator |
| 1snTxTxTx | |
| 1 | Indicator |
| sn | Sign of temperature |
| TxTxTx | Maximum temperature 0600-1800 UTC in tenths of a degree |
| 2snTnTnTn | |
| 2 | Indicator |
| sn | Sign of temperature |
| TnTnTn | Minimum temperature 1800-0600 UTC in tenths of a degree |
| 3EsnTgTg | |
| 3 | Indicator |
| E | State of ground without snow or measurable ice cover |
| sn | Sign of temperature |
| TgTg | Grass minimum temperature rounded to nearest whole degree |
| 4E'sss | |
| 4 | Indicator |
| E' | State of ground with snow or measurable ice cover |
| sss | Depth of snow |
| 8NsChshs | |
| 8 | Indicator |
| Ns | Amount of individual cloud layer |
| C | Form of cloud (Table 19) |
| hshs | Height of base of cloud layer |
| 9SpSpspsp | |
| 9 | Indicator |
| SpSpspsp | This group is included when necessary to report special phenomena. |
General information:
Up to four layers of significant cloud can be reported (using 8NhChshs groups). The rules for the selection of significant cloud layers are:
1. The lowest layer of any amount
2. The next lowest layer of 3 oktas (eighths) or more.
3. The next lowest layer of 5 oktas or more.
4. Any cumulonimbus cloud not already reported under 1, 2 or 3 above, regardless of amount.
Clouds are reported in order of ascending height. Cumulonimbus cloud reported under rule 4 above would be inserted between the other groups at its correct height level - regardless of the amount of Cumulonimbus being reported.
| 555 | National indicator (This section is not sent when there are no data to report) |
| 1V'f'/V'f''f'' | |
| 1 | Indicator |
| V'V' | Visibility in metres (reported when visibility is less than 100 m) |
| (f')f'f' | Speed in knots of the maximum gust in the past hour (>33 kts) |
| 2snTwTwTw | |
| 2 | Indicator |
| sn | Sign of temperature |
| TwTwTw | Sea temperature in tenths of a degree |
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