Don't worry, there's a coffee shop half way up.
The Golden Mount (phu khao thong) was built within the Wat Saket grounds by Rama I’s grandson, King Rama III in the early 1800s. Rising some 58 metres above ground, the steep human-made hill is crowned at its top by a large golden chedi that’s believed to house relics of the Buddha. Waterfalls, flower gardens and prayer bells are placed along the 320 stairs that wind to the top. It sounds exhausting, but the stairs aren't very steep and a coffee shop and several other stop-offs make it manageable. Be sure to bang the massive gong after making a wish.
After passing through an enclosed shrine area, a steep stairwell takes you to an open-air platform centred around the main chedi at the very top of the structure. Here, a small crowd of locals are usually found offering flowers, candles, incense, and prayers as a few tourists soak in the atmosphere. Even on the hottest of days a refreshing breeze gently chimes tiny gold leaf bells, each representing a donation from the lay community.