Temperature is not a vector. At any particular point, it is completely specified by a single number, and has no directional quality. This figure represents an area in which the temperature varies from point to point; higher temperature corresponds to white and lower temperature to black.
Don't be confused by the fact that the temperature can be different at different places; this does not change the fact that the temperature at any particular place is specified by one number only. So your answer was wrong. Try again!