The Wachirathan Waterfall (pronounced "wah-chee-rah-TAHN"; also spelled Vachirathan) was the second major waterfall on the way up to the summit of Doi Inthanon. Of all the waterfalls we saw in Doi Inthanon National Park, we thought this one had the most power and spray, and it was probably the most impressive of the lot on the mountain's slopes.
Even though our guide told us that this was 80m in cumulative height, I was thinking it was more like 40m or so. The falls was also wide, but segmented during our visit as the far right section of the falls were stringier than the left. I reckon during the wet season, this would be both wide and raging.
But even though Julie and I visited during the start of the Dry Season, the falls had enough volume to produce plenty of mist and rainbows. There were also parts of the loop walk around the waterfall (especially just downstream of it in its lower reaches) that was quite muddy and slippery as the path was drenched in its mist. So I have no doubt that this was a year-round waterfall though I'd imagine the flow becomes lighter as the Dry Season progresses.
Moreover, I reckon because of the ease of access, this was probably the most popular of the three waterfalls on Doi Inthanon's slopes. All in all, we spent roughly 35 minutes to do the loop walk plus all the picture taking.
Directions: Since we were escorted, we can't give exact directions. However, we can say that it took us about 25 minutes drive downhill from the Siriphum Waterfall or about 20 minutes uphill from the Mae Klang Waterfall.