Best to check. Light casual clothes are recommended for the trek due to hot, humid weather around Pinatubo. Shorts are preferable as there are many stream crossings. A heavy load will really slow you down. Filipino is the national language, although English is widely used, especially in business and government.
Public sanitation is a problem in many rural areas.
Drink only bottled, boiled or treated water. Guides with first-aid training are usually provided in a tour package. The plains, covered with gray ash that reflects sunlight, can make a warm day hotter. Bring plenty of bottled water. Since fine dust can seep in and cause discomfort, some tour agencies provide heavy-duty masking tape to wrap around the ends of socks or shoes.