No, the water doesn't get warmer, the springs are always 72 degrees.
The water temp stays 72F year round. Because of the ambient air temp, the water will feel much warmer at night than it does during the daytime. When I camp there and dive, the water is very cold during the day but after dark it feels like walking into bath water.
The springs do not, since they are spring fed. Its the same temp all year. The river gets warmer though.
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