In this paper we document instances where change in the magnitude of natural oil seepage coincided with fluctuations of fluid temperature in a seafloor mud volcano. Oil slicks were detected floating near commercial oil fields in the northern Gulf of Mexico in a time series of six satellite synthetic aperture radar (SAR) images collected over a 10 month interval. The oil escaped naturally from a complex of fluid expulsion features at seafloor depths of about 600 m. One of these features was a 50-m-wide, mud- and brine-filled crater. Temperature in the crater fluctuated rapidly during an interval of ∼1 yr (minimum 6.1 °C, maximum 48.3 °C, mean 26.1 °C, standard deviation 9.07). The areas of the oil slicks in the SAR images fluctuated repeatedly between <10 and >1000 ha. The largest oil slicks detected by SAR occurred along with the fastest increase in fluid temperature.