There’s a hot spring that mixes with a river that creates a 100-meter long hot spring.  I’m not sure what the temperature was closer to the actual hot spring, but as more snow melt springs flow into the river, it cools off quite quickly downstream making it marginally warm in comparison to the freezing outside temp.  Starting from the parking lot at the end of the gravel road, it took us approximately 75 minutes to hike uphill to the hot spring river.  The trail was pretty muddy, so you’ll want to bring boots.  There are various changing areas there along the wooden planked walkways with space to store your gear.