Hourly Elements: ID ELEMENT Unit rain Precipitation Amount mm temp Air Temperature °C wetb Wet Bulb Air Temperature °C dewpt Dew Point Air Temperature °C vappr Vapour Pressure hpa rhum Relative Humidity % msl Mean Sea Level Pressure hPa wdsp Mean Hourly Wind Speed kt wddir Predominant Hourly wind Direction kt ww Synop Code Present Weather - decode below w Synop Code Past Weather - decode below sun Sunshine duration hours vis Visibility m clht Cloud Ceiling Height - if none value is 999 100s feet clamt Cloud Amount okta Indicators (i) Description - Decode irain Rainfall Indicators: 0. satisfactory. 1. deposition. 2. trace or sum of precipition. 3. trace or sum of deposition. 4. estimate precipitation. 5 estimate deposition. 6. estimate trace of precipitation. itemp Temperature Indicators: 0. positive. 1. negative. 2. positive estimated. 3. negative estimated. 4. not available. iwb Wet Bulb Indicators: 0:positive. 1. negative. 2. positive estimated. 3. negative estimated. 4. not available. 5. frozen negative. iwdsp Wind Speed Indicators: 2. Over 60 minutes. 4. Over 60 minutes and defective 6 Over 60 minutes and partially defective. 7. n/a iwddir Wind Direction Indicators: 2. Over 60 minutes. 4. Over 60 minutes and defective 6 Over 60 minutes and partially defective. 7. n/a WW Code: Present Weather Weather at time of observation. Decode - SYNOP - ww in group 7wwW1W2 WW=00-19 No precipitation, fog,(except for 11 and 12), duststorm, sandstorm, drifting or blowing snow at the station at the time of observation or, except for 09 and 17, during the preceeding hour 00 Cloud development not observed or observable }characteristic 01 Clouds dissolving or becoming less developed }state of sky 02 State of sky on the whole unchanged }during the 03 Clouds generally forming or developing }past hour 04 Visibility reduced by smoke haze 05 Haze 06 Widespread dust in suspension in the air, not raised by wind at or near the station at the time of observation. 07 Dust or sand raised by the wind at or near the station at the time of the observation, but no well-developed dust whirl(s), and no sandstorm seen: or, in the case of ships, blowing spray at the station 08 Well developed dust whirl(s) or sand whirl(s) seen at or near the station during the preceding hour or at the time of observation, but no duststorm or sandstorm. 09 Duststorm or sandstorm within sight at the time of observation, or at the station during the preceding hour 10 Mist 11 Patches of } shallow fog or ice fog 12 More or less continuous } less than 2 m on land or 10 m at sea 13 Lightning visible, no thunder heard 14 Precipitation within sight, not reaching the ground or surface of sea 15 Precipitation within sight, reaching ground or the surface of the sea, but distant, i.e. estimated to be more than 5 km from the station 16 Precipitation within sight, reaching the ground or the surface of the sea, near to, but not at the station 17 Thunderstorm, but no precipitation at the time of observation 18 Squalls } at or within sight of ) the station during 19 Funnel cloud(s) during the preceding hour or at time of observation WW=20-29 Precipitation, fog, ice fog or thunderstorm at the station during the preceeding hour but not at the time observation 20 Drizzle (not freezing) or snow grains } 21 Rain (not freezing) } Not 22 Snow } falling 23 Rain and snow or ice pellets } as shower(s) 24 Freezing drizzle or freezing rain } 25 Shower(s) of rain 26 Shower(s) of snow, or of rain and snow 27 Shower(s) of hail, or of rain and hail 28 Fog or ice fog 29 Thunderstorm (with or without precipitation) WW=30-39 Duststorm, sandstorm, drifting or blowing snow 30 Slight or } has decreased during the preceding hour 31 moderate duststorm }no appreciable change during the preceding hour 32 or sandstorm } has begun or increased during the preceding hour 33 Severe } has decreased during the preceding hour 34 duststorm } no appreciable change during the preceding hour 35 or sandstorm } has begun or increased during the preceding hour 36 Slight or moderate drifting snow } Generally low 37 Heavy drifting snow } (below eye level) 38 Slight or moderate blowing snow } Generally high 39 Heavy blowing snow } (above eye level) WW=40-49 Fog or ice fog at the time of observation 40 Fog or ice fog at a distance at the time of observation, but not at the station during the preceding hour,the fog or ice fog extending to a level above that of the observer 41 Fog or ice fog in patches 42 Fog or ice fog, sky visible } has become thinner during 43 Fog or ice fog, sky obscured } preceding hour 44 Fog or ice fog, sky visible } no appreciable change 45 Fog or ice fog, sky obscured } during the preceding hour 46 Fog or ice fog, sky visible } has begun or has become thicker 47 Fog or ice fog, sky obscured } during the preceding hour 48 Fog or ice fog, sky visible 49 Fog or ice fog, sky obscured WW=50-59 Drizzle 50 Drizzle, not freezing, intermittent } slight at time 51 Drizzle, not freezing, continuous } of observation 52 Drizzle, not freezing, intermittent } moderate at time 53 Drizzle, not freezing, continuous } of observation 54 Drizzle, not freezing, intermittent } heavy (dense) at time 55 Drizzle, not freezing, continuous } of observation 56 Drizzle, freezing, slight 57 Drizzle, freezing, moderate or heavy (dense) 58 Drizzle and rain, slight 59 Drizzle and rain, moderate or heavy WW=60-69 Rain 60 Rain, not freezing, intermittent } Slight at time 61 Rain, not freezing, continuous } of observation 62 Rain, not freezing, intermittent } Moderate at time 63 Rain, not freezing, continuous } of observation 64 Rain, not freezing, intermittent } Heavy at time 65 Rain, not freezing, continuous } of observation 66 Rain, freezing, slight 67 Rain, freezing, moderate or heavy 68 Rain or drizzle and snow, slight 69 Rain or drizzle and snow, moderate or heavy WW=70-79 Solid precipitation not in showers 70 Intermittent fall of snowflakes } slight at time 71 Continuous fall of snowflakes } of observation 72 Intermittent fall of snowflakes } moderate at time 73 Continuous fall of snowflakes } of observation 74 Intermittent fall of snowflakes } heavy at time 75 Continuous fall of snowflakes } of observation 76 Diamond dust (with or without fog) 77 Snow grains (with or without fog) 78 Isolated star-like snow crystals (with or without fog) 79 Ice pellets WW=80-99 Showery precipitation, or precipitation with current or recent thunderstorm 80 Rain shower(s), slight 81 Rain shower(s), moderate or heavy 82 Rain shower(s), violent 83 Shower(s) of rain and snow mixed, slight 84 Shower(s) of rain and snow mixed, moderate or heavy 85 Snow shower(s), slight 86 Snow shower(s), moderate or heavy 87 Shower(s) of snow pellets or small hail }- slight 88 with or without rain or rain and snow mixed }- moderate or heavy 89 Shower(s) of hail, with or without rain or }- slight 90 rain and snow mixed, not associated with thunder }- moderate or heavy WW=91-94 Thunderstorm during the preceeding hour but not at time of observation 91 Slight rain at time of observation 92 Moderate or heavy rain at time of observation 93 Slight snow, or rain and snow mixed, or hail2 at time of observation 94 Moderate or heavy snow, or rain and snow mixed, or hail1 at time of observation WW=95-99 Thunderstorm at time of observation 95 Thunderstorm, slight or moderate, without hail2 but with rain and or snow at time of observation 96 Thunderstorm, slight or moderate, with hail2 at time of observation 97 Thunderstorm, heavy, without hail2 but with rain and or snow at time of observation 98 Thunderstorm combined with dust storm or sandstorm at time of observation 99 Thunderstorm, heavy, with hail2 at time of observation * The expression at the station refers to a land station or a ship 1 Tornado cloud or waterspout 2 Hail, small hail, snow pellets W - Code: Past Weather Weather during past hour Decode - SYNOP – W1,W2 in group 7wwW1W2 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