Agriculture is the science and art of plant and livestock cultivation. Modern ways of agriculture, plant breeding, chemicals such as pesticides and fertilizers and technological developments have sharply increased yields. Global warming affects agriculture through changes in average temperatures and rainfall resulting in changes in pests and diseases; changes in atmospheric carbon dioxide and ozone concentrations at the ground level. To minimize the wastage of water and automate the irrigation system, a smart irrigation system is proposed in this paper. This irrigation system supplies water to the field based on the weather predicted by the weather prediction system as well as the moisture level in the field. Agriculture land is divided into subplots and a mechanism is proposed to water these subplots by having a small motor for each of the subplot rather than having one large motor for the entire field. Unlike conventional cultivation, different types of crops can be grown in these subplots. Different crops require different water levels which can be adjusted using the motor and valve mechanism present in each subplot. The weather prediction system works by considering humidity, light intensity, pressure, and temperature on the field which are measured by using sensors. Smart sensor and Internet of Things (IoT) based system is used for communicating the information to the farmers’ mobile which will help them to understand the water levels in the subplots. The overflow of water due to rain is also taken care in the proposed system. During heavy rains, if the moisture sensor indicates that the plot is flooded, then respective valves will be immediately opened, thereby driving out the water from the field and protecting the crops. In the subplot system as the flow of water is not over a large region the chances of soil erosion are greatly diminished.