It is not as hot at some distance at the side of a flame as the same distance above it. Why is this so?

PLACEHOLDER ANSWER - the answer is an explanation. Air heated by the flame becomes less dense and rises, carrying heat upward by convection. Above the flame, heat arrives by both convection and radiation, but at the side it arrives almost only by radiation (air conducts heat poorly). So it is much hotter above the flame than at the same distance to the side.