The Republic of Guinea experiences a tropical climate marked by a dry season influenced by the Harmattan winds and a rainy season driven by the West African monsoon, with a mean annual rainfall of approximately 1835 mm. This study examines precipitation trends using meteorological data from twelve synoptic stations over the period 1983-2013. Twelve precipitation indices, classified into four categories: hydrological, agro-hydrological, agronomic, and extreme precipitation indices, were analyzed to assess spatiotemporal variability. Trends were evaluated using the Mann-Kendall test at significance levels of 90%. Results reveal a pronounced north-south gradient in rainfall distribution, with the south receiving more abundant and intense precipitation. Agro-hydrological indices indicate that the rainy season begins around mid-January in southern regions, while the monsoon onset occurs nationwide by May 1st. Seven-day wet spells are frequent in the south, whereas dry spells predominate in northern areas. Conakry exhibits a high frequency of extreme wet events, in contrast to northern regions, which are more susceptible to severe dry conditions. Trend analysis shows a significant increase in wet-day indices, while indices related to dry days and extreme rainfall events display a statistically significant decrease.
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