Penang vs Koh Samui

Based on sunshine hours, rain days, comfortable temperatures, and humidity levels, Koh Samui edges ahead as the better destination in September. Koh Samui offers 9 hours of daily sunshine with only 22 rain days, while Penang sees 9 sunshine hours and 26 rain days.

Penang can feel quite hot at 29°C, so plan for heat. Koh Samui is also comfortable at 26°C.

For travelers who prioritize dry weather, Koh Samui is the stronger choice in September.

Penang reaches an average high of 29°C (84°F) and drops to 25°C (77°F) at night during September. The daily temperature range is 4°C, meaning relatively stable temperatures from day to night.

Koh Samui averages 26°C (79°F) for the high and 23°C (73°F) for the low, with a daily range of 3°C. The 3°C difference is noticeable but not dramatic.

Both cities are in the Northern Hemisphere, so they share the same seasonal pattern in September.

Penang receives approximately 250 mm of rainfall across 26 rain days during September. Rain is frequent, so waterproof gear is essential.

Koh Samui sees 140 mm over 22 rain days. That makes Koh Samui the drier option by 4 rain days and 110 mm of total precipitation.

Both cities share similar humidity levels at 82%.