Weather observation is the acquisition of weather data for daily use, operation planning and research.

Observations can be made:

Manual: collection of information by human observation;

• Visual: by direct observation of phenomena;
• Sensoric: by collection of instrument data.
• Imaging: through (manual) picture documentation. 

Automatic (Instrumental): using measurement instruments, also called "measurement".

• Surface measurements (mostly through weather "stations" or "buoys").
• Radiosonde: through weather balloons which cross the atmospheric (also called "soundings").
• Remote sensing: through satellites or ground-bases systems (radar) which cover and collect information from larger areas.

Weather information systems over larger scale as wells as historic and forecast systems are almost entirely based on Automatic observations.

Observation covers less than 1% of the atmospheric conditions on Earth; 99% of all  weather information available today is generated by simulation