20°C is above the ideal 16–18°C range, but not dramatically. Most people will still fall asleep — it's staying asleep through the early hours that becomes harder, because your body can't complete its natural cooling cycle.

The dew point — 18°C — is the real problem tonight. High dew point means your sweat can't evaporate, which is your body's primary cooling mechanism. This is why humid heat feels worse than dry heat at the same temperature, and why a fan helps more than you'd expect.

A 5.8°C drop between bedtime and 4am is substantial. This natural cooling aligns with your circadian rhythm — your body temperature dips in the early hours, and the environment cooling alongside it produces the deepest sleep of the night.