Methodical documentation and consequent incorporation of Indigenous knowledge in seasonal rainfall forecasting is one of the promising ingenuities that need to be explored. Historically and to date, local communities in different parts of the world have continued to rely on Indigenous Knowledge (IK) to conserve the environment and deal with natural disasters. Despite these, indigenous method of weather and climate prediction is under threat of disappearance due to lack of coordinated research to investigate the accuracy and reliability of Indigenous Knowledge forecasting. This study therefore investigated the indigenous methods of rainfall prediction among farmers and fisher-folks in Ethiope East Local Government Area of Delta State, Nigeria. Specifically, the study aimed at identifying the indigenous bio-indicators used for rainfall prediction and the perception of farmers and fisher-folks on the level of reliability of indigenous knowledge compared to the conventional weather forecasting methods in the study area. Through a multi-stage sampling, 220 questionnaires were administered to farmers and fisher-folks randomly selected from 4 settlements with concentrated farming and fishing activities in Ethiope LGA. The study reveals that the farmers relied heavily on experiences obtained from the combinations of plant phonology, animals and insects’ behaviors in predicting changing weather and Climate pattern in addition to using their knowledge of meteorological and astronomical indicators, as the farmers adjudged the method as very reliable with high degree of accuracy compared to the conventional weather forecasting method. The study thus conclude that IKS can provide significant value and boosts in the improvements of forecasting accuracy and reliability if analytically integrated in conventional forecasting system as the documentation of IKS will be a good resource for the establishment of effective adaptation strategies to lessen the impacts of climate change.