Khao Yai National Park’s temperature is generally a little lower than in the plains. In fact, it can be distinctly chilly at night. The Rainy Season is in May-October, it does rain most days but there are also long dry spells. This is the best time of year to see the waterfalls.
For Cold season in November- February, the weather is sunny and cool. It is the ideal time for hiking. Hot Season is in March-April. The maximum temperature does reach 30°C but the temperature is still comfortably cooler than in the plains. The waterfalls are at their least spectacular.