A total air temperature probe comprising: a housing including: an inlet scoop; an outlet; a main airflow passage extending from the inlet scoop to the outlet, the main airflow passage including: a first side surface extending from the inlet scoop to the outlet, the first side surface including a first planar portion extending from the inlet scoop; a second side surface opposite the first side surface and extending from the inlet scoop to the outlet, the second side surface including a second planar portion extending from the inlet scoop; an upper inlet surface extending from the inlet scoop; a lower inlet surface opposite the upper inlet surface and extending from the inlet scoop; an upper outlet surface extending from the upper inlet surface to the outlet; and a lower outlet surface opposite the upper outlet surface and extending from a split point in the housing to the outlet; an exit that extends through the housing; and a total air temperature sensor flow passage that branches off from the main airflow passage and extends to the exit; and a sensor assembly positioned in the total air temperature sensor flow passage; wherein the upper inlet surface and the lower inlet surface are substantially parallel and are configured to be substantially parallel with oncoming airflow; wherein the total air temperature sensor flow passage branches off from the main airflow passage at a location between the lower inlet surface and the lower outlet surface; and wherein the lower inlet surface is substantially planar; characterised by: the first side surface including: a first concave portion extending from the first planar portion to the outlet; and the second side surface including: a second concave portion extending from the second planar portion to the outlet; wherein the first concave portion and the second concave portion are consistently concave toward the outlet and have constant curvatures and wherein the upper outlet surface is consistently concave toward the outlet and has a constant curvature. a housing including: an inlet scoop; an outlet; a main airflow passage extending from the inlet scoop to the outlet, the main airflow passage including: a first side surface extending from the inlet scoop to the outlet, the first side surface including a first planar portion extending from the inlet scoop; a second side surface opposite the first side surface and extending from the inlet scoop to the outlet, the second side surface including a second planar portion extending from the inlet scoop; an upper inlet surface extending from the inlet scoop; a lower inlet surface opposite the upper inlet surface and extending from the inlet scoop; an upper outlet surface extending from the upper inlet surface to the outlet; and a lower outlet surface opposite the upper outlet surface and extending from a split point in the housing to the outlet; an exit that extends through the housing; and a total air temperature sensor flow passage that branches off from the main airflow passage and extends to the exit; and an inlet scoop; an outlet; a main airflow passage extending from the inlet scoop to the outlet, the main airflow passage including: a first side surface extending from the inlet scoop to the outlet, the first side surface including a first planar portion extending from the inlet scoop; a second side surface opposite the first side surface and extending from the inlet scoop to the outlet, the second side surface including a second planar portion extending from the inlet scoop; an upper inlet surface extending from the inlet scoop; a lower inlet surface opposite the upper inlet surface and extending from the inlet scoop; an upper outlet surface extending from the upper inlet surface to the outlet; and a lower outlet surface opposite the upper outlet surface and extending from a split point in the housing to the outlet; a first side surface extending from the inlet scoop to the outlet, the first side surface including a first planar portion extending from the inlet scoop; a second side surface opposite the first side surface and extending from the inlet scoop to the outlet, the second side surface including a second planar portion extending from the inlet scoop; an upper inlet surface extending from the inlet scoop; a lower inlet surface opposite the upper inlet surface and extending from the inlet scoop; an upper outlet surface extending from the upper inlet surface to the outlet; and a lower outlet surface opposite the upper outlet surface and extending from a split point in the housing to the outlet; an exit that extends through the housing; and a total air temperature sensor flow passage that branches off from the main airflow passage and extends to the exit; and a sensor assembly positioned in the total air temperature sensor flow passage; wherein the upper inlet surface and the lower inlet surface are substantially parallel and are configured to be substantially parallel with oncoming airflow; wherein the total air temperature sensor flow passage branches off from the main airflow passage at a location between the lower inlet surface and the lower outlet surface; and wherein the lower inlet surface is substantially planar; characterised by: the first side surface including: a first concave portion extending from the first planar portion to the outlet; and the second side surface including: a second concave portion extending from the second planar portion to the outlet; wherein the first concave portion and the second concave portion are consistently concave toward the outlet and have constant curvatures and wherein the upper outlet surface is consistently concave toward the outlet and has a constant curvature.