Scalars have magnitude but no direction, unlike vectors which have both. Temperature, being scalar, does not require directional information.
Pro Tip 2/3
Physical Properties
In physics, scalar quantities often describe physical properties that are not directional. The energy in a scalar form just states the amount, not where it's going.
Pro Tip 3/3
Scalar Operations
When used in operations like multiplication, scalars can change the size of another quantity. Multiplying a velocity vector by a scalar changes its speed but not direction.