Not necessarily. A lot of the wells around my place (same region) are fed by melting snowpack, which lasts most of the year, that seeps into a more-or-less isolated fractured granite acquifer. It does eventually drain into a warmer acquifer basin, but the water that comes out of the granite is positively icy all year. Wells that are closer to the major water basin in the valley get warmer (to boiling in some places). At the springhead for the creek that runs by my place, the water is probably no more than 40 all year. Springs a mile or two down the slope are warmer though, and taste a bit like sulfur.