In making an observation while there is precipitation, note the time precipitation began and ended. Wind has a speed and a direction. Wind speed is measured by an anemometer. Wind direction can be estimated by noting which way a flag is blowing. Remember wind direction is taken as the direction the wind is coming from.
Visibility is generally a good indicator of precipitation intensity.
Note the distance to landmarks near the observation spot and determine what landmarks are visible when there is significant precipitation. Is the precipitation associated with a thunderstorm, if so the intensity of the thunderstorm should be noted. Is there a tornado associated with the thunderstorm. Prices are highly variable.