Use 'hot up' to describe situations that are increasing in excitement, tension, or competitiveness.

Excitement Buildup

'Hot up' is casual and often used in spoken English or informal writing.

Conversational Tone

Understand that 'hot up' can be figurative, not just literal, to express intensifying situations.

Use 'hot up' to talk about the temperature increasing in a given location or period.

Use 'hot up' to describe weather changes, especially transitions to hotter seasons like summer.

'Hot up' often suggests a gradual increase in heat, not an immediate change.