[′thərd ¦ȯr·dər ‚klī·mə·tə′läj·ə·kəl ′stā·shən] (climatology) As defined by the World Meteorological Organization, a station, other than a precipitation station, at which the observations are of the same kind as those at a second-order climatological station, but are not so comprehensive, are made once a day only, and are made at other than the specified hours.