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This work presents a catalog of daily precipitation in the Balearic Islands created with data from AEMET assistant observers, including registers since 1912. The original digital daily data file has been interpolated onto a regular 100m resolution grid (namely PREGRIDBAL), defined with the aim of becoming a valid standard for future methodological improvements and catalog upgrades. Daily precipitation amounts on each grid-point are calculated using an analysis method based on ordinary Kriging, using the daily anomaly with respect to the annual mean for all available observations each day. Due to quality concerns, the time span for products derived from the catalogue is limited to the 1950-2009 period. Therefore, from the elementary daily maps, monthly-, annual-, quinquennial-, and decadal-accumulations are produced. Similarly, the catalog allowed for quantification of climate trends in rainfall amounts in the Balearic Islands, with the significant advantage of minimising the biases originated from heterogeneities in the spatial distribution of stations across the archipelago. Results show a general decrease in precipitation during the 1950-2009 period. From 1950 to 1979, the average annual precipitation across the islands was 624,3mm, while from 1980 to 2009 diminished to 555,36mm. Changes in precipitation patterns, which vary among the different areas, are also detected. Most significant reductions (over 80% significance on the trend) are found in the north half of the archipelago and especially in Mallorca, where the Tramuntana mountain range stands out. All seasonal trends show a decrease, with values ranging between 1 and 3mm per decade, with the exception of autumn, which reaches up to 7mm per decade. October shows the most dramatic decrease (-10,34mm per decade) and, conversely, September and November show an increase in precipitation (3,28 and 1,82mm per decade, respectively) with a statistical significance above 85% in almost all the archipelago, and even exceeding 95% in the Pitiüses. [ABSTRACT FROM AUTHOR]