Apparatus and associated methods relate to measuring temperature of a fluid within a hydraulic vessel using a temperature probe that has an annular recess circumscribing a projecting sensor tip. The annular recess is configured to permit fluid flow into an aperture region of a vessel wall through which the temperature probe contacts the fluid within the hydraulic vessel. Because the temperature probe projects from the annular recess within the aperture, a net projection dimension, as measured in a projection direction from an interior surface of the vessel wall proximate the aperture to a sensor, is less than a gross projection dimension, as measured in the projection direction from a bottom of the annular recess to the sensor tip. In some embodiments, this configuration advantageously improves a ratio of thermal conductivity between the fluid and the temperature probe and thermal conductivity between the temperature probe and a sensor housing.