Hong Kong
Low risk — Hong Kong winters are mild and generally dry; visibility usually good if an event is held.
If a harbourfront event returns, expect very dense crowds and early road closures (from ~6 PM) around the venue; historically pier/promenade crush risk.
MTR is the recommended access with extended service on NYE; harbour crossings become heavily congested. Specific arrangements depend on the (not-yet-announced) 2027 event.
Alcohol available at licensed venues, harbour cruises and rooftop bars (e.g. Tsim Sha Tsui and Central); ticketed events sell out early.
Jan 1 is a public holiday; MTR and most services operate.
Other cities celebrating New Year's Eve