December is Cambodia's cool, dry season—pack lightweight breathable clothes, a light long-sleeve for evenings, a hat, sunscreen, and comfortable walking shoes for temple tours. Carry essential medications, insect repellent for rural dawn/dusk, and copies of e-visa confirmations. Expect short-sleeve days and cooler mornings; humidity is lower, making temple visits comfortable. Book accommodations and Angkor/Phnom Penh guided tours early to secure preferred times, especially for Christmas and New Year weeks. Allow at least three hours at Los Angeles International Airport (LAX) for international departures and anticipate extra arrival crowds at Phnom Penh International Airport (PNH) during holiday windows. Keep digital and printed travel documents, notify your bank of international travel, and consider travel insurance that covers delays and medical evacuation. CTA: Check your passport validity, apply for a Cambodia e-visa if required, and pack smart for December weather at PNH.