Weather will likely play an important role when you plan your trip to Undara Volcanic National Park, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually December and November with an average temp of 74°F, while the coldest months are August and July with an average of 65°F. The rainiest months in Undara Volcanic National Park are January, February, March, and December, with each month seeing an average of 9 inches of rainfall.