Changi's "jewel" layover, and the heat plan

Changi Airport is a destination: the Jewel complex with its indoor waterfall is landside, free, and open late, so even a long layover is pleasant, and the airport runs free city tours for transit passengers with enough time. Singapore is hot and humid every day of the year; plan outdoor sightseeing for early morning and evening, and use the air-conditioned underground passages and malls at midday, as locals do. Carry an umbrella for the afternoon downpours.