Over the course of the year, the temperature in Tarragona typically varies from 40Â°F to 84Â°F and is rarely below 31Â°F or above 88Â°F. The warm season lasts for 91 days, from June 19 to September 18, with an average daily high temperature above 78Â°F. The hottest day of the year is August 6, with an average high of 84Â°F and low of 70Â°F. The cool season lasts for 122 days, from November 19 to March 21, with an average daily high temperature below 62Â°F.