Overview: Marco IslandMarco Island (United States of America) is a place with a tropical climate. Temperatures during the day are in the range from 25 °C (76 °F) in January to 33 °C (92 °F) in August. The highest sea temperatures in Marco Island are in August with 30 °C (86 °F) and the lowest in January with 21 °C (70 °F). Temperatures during the night go from 13 °C (55 °F) in January to 24 °C (75 °F) in August. The least rainy month in Marco Island is April with its 5 days of rain, the rainiest month is August, when it rains 15 days.