In this study, within the hour parametric probability density functions are calculated by using TEC (Total Electron Content) estimates. TEC estimates are obtained from IONOLAB-TEC method by using TNPGN-Active GPS network. GPS stations are placed at intervals with an average range of 80-100 km distance, between the years 2009 and 2012, provided input for calculation of probability density functions. The IONOLAB-TEC values within-an-hour are grouped depending on latitude, longitude, region and season. PDF estimates of IONOLAB-TEC are obtained and grouped according to latitude and longitude variation. It is observed that TEC values have a strong hourly, seasonal and positional dependence On east-west direction, the growing trend shifts according to sunrise and sunset times. In this context, geography of Turkey is separated into regions which are in 2 in latitude and 30 in longitude. A representative GPS station is chosen within each region. Within-the-hour pdf estimates are grouped into ionospheric seasons as Winter, Summer, March equinox and September equinox. In winter and summer seasons, Lognormal distribution is observed During equinox seasons Weibull distribution is observed more frequently. Pdf estimates of TEC of the ionosphere over Turkey will contribute to developing a regional and seasonal random field model.