Currently, Indonesia is still struggling against the Coronavirus, the number of cases of the Coronavirus is increasing every day. The virus that began to attack around December 2019 has become a pandemic and is causing serious problems because there is still no vaccine to prevent transmission. The Government of the Republic of Indonesia as the party responsible for this pandemic has made various efforts including the lockdown method in the form of a Large-Scale Social Restriction (PSBB) policy. Besides that, another effort is to present a digital information portal that can be accessed and able to present the development status of coronavirus patients. With the development of information and communication technology, this research is a find correlation between weather and Covid-19 Using Data Mining Algorithm in processing data sources from the government to produce knowledge that can be used to make decisions. The research data used came from Covid-19 surveillance data of the Ministry of Health of the Republic of Indonesia and the climatic conditions in Surabaya Indonesia in the form of the average temperature (°C), the average humidity (%), the average duration of sunlight (hour) taken from the Department of Meteorology of the Republic of Indonesia. Based on the results of the study it was found that the weather affected the number of Covid-19 patients. The highest order of correlation is the average duration of sunlight (hour), the average temperature (°C), the average humidity (%).