A temperature sensor approximates fluid temperature averaged across a location range by including an outer armour layer. Several resistance temperature detectors are spaced in an electrical circuit which is then protected in the outer armour layer. The outer armour layer is woven without any seam to enhance its longitudinal thermal conductivity. In the preferred weave, twenty-four stands of sixteen metal threads each are helically woven. The electrical circuit is sealed interior to the armour layer so any condensation or moisture within the armour layer does not affect the circuit. The armour layer is sealed on its ends to the sheathing of the underlying circuit, so the armour layer provides stress relief across the connections of the resistance temperature detectors to the circuit. The resulting sensor is robust and durable, as well as very flexible.