An extraordinary stable auroral red (SAR) arc was observed on the night of March 5/6, 1981 (EST) at a field station near Albany (42.63 ¿N; 73.98 ¿W), New York with a multicolar meridian scanning photometer and a 15-cm high-resolution Fabry-Perot interferometer. The acr was extraordinary in the sense that: (a) it was the most intense arc (~2.2 kR) observed during the past twelve years at Albany, New York; (b) it was a multiple arc consisting of two SAR arcs (the major arc occurred between zenith angles of 40¿ (L = 2.7) amd 54 ¿S (L = 2.5) throughout the observation period, and the minor arc occurred in close proximity for a duration of only one hour; (c) a visible aurora was not sighted from Albany during the observation period. Thermospheric temperatures were derived from Doppler line profiles of the [0I> 6300¿ emission, obtained within the arc and outside the arc at zenith angles of 70 ¿S, 50 ¿N, and 70 ¿N. The temperature within the arc were quite stable with respect to time, even during the period of very rapid and large decrease in the arc intensity, and they were approximately equal to those measured at 70 ¿N. The temperatures at 70 ¿S, which varied considerably in time, were different from those at 50 ¿N or 70 ¿N. The temperatures within the arc were generally higher than those at 50 ¿N or 70 ¿S. The observed enhancement of the temperatures within the arc is much greater than the value predicted by the two-dimensional model calculations of the SAR arc.