Basic climatological features over any region are hidden in many meteorological variables, especially in precipitation and temperature records. Among these features the single most important one is the periodicity of different harmonics. Identification of periodic features require regionally and temporally representative data sets and treatment methodology for depicting their amplitudes, frequencies, phase angles and basic statistical parameters. In this paper, only precipitation records are considered for depicting spatial periodic features over the whole of Turkey. Herein, more than 200 precipitation records, uniformly scattered all over Turkey, are studied with basic harmonic analysis revealing the various climatological patterns of Turkey in the form of contour maps. It is observed that only the first and the second harmonics are sufficient to explain more than 90% of the climatological variations in Turkey. Copyright (C) 1999 Royal Meteorological Society.