<p>A novel method to quantify the magnitude of upwelling is presented wherein using 8 day average sea surface temperature (SST) an intensity of cooling is identified. The step-wise average SST from the coast to offshore is estimated using 20 km legs (strips) that are parallel to the coast. The difference of SST between the coastal cooler waters and the warmest offshore waters (reference SST) called upwelling strength (US) is estimated and summed as upwelling intensity (UI), was analyzed across ten evenly spaced coastal regions of western Arabian Sea (WAS). Besides identifying the offshore extent of the local upwelling, this method also delineates the presence of advected cooler waters not directly linked to local upwelling, if any. This method enables comparison of upwelling in a region during different times and also between different regions and can form a baseline for estimating the magnitude of upwelling in different upwelling regimes of the world ocean. Some of the important new findings are the highest US at coastal as well as offshore (at 400 km) legs in most of the regions along Oman in August and occurring a month later than that along Somalia. Within the Oman coast, the highest UI is during 8-day average (hereafter referred as cycle) represented by 8th August along south-central Oman while along Somalia, the highest UI is observed during 8-day cycle represented by 15th July off northern Somalia. All along the WAS the UI decreases from 2003 to 2021 and is a matter of great concern for fisheries with highest decrease of 25.6% off northern Oman. The validity of the method is established based on the high positive significant correlation that is found and which is expected between UI and Ekman mass transport as well as Chlorophyll-a concentration.</p>