Heat flow measurements along much of the San Andreas fault (SAF) constrain the apparent coefficient of friction (¿app) of the fault to 0.2 should be detectable even with the sparse existing observations, implying that ¿app for the creeping section is as low as the surrounding SAF. Because the creeping section does not slip in large earthquakes, the mechanism controlling its weakness is not related to dynamic processes resulting from high slip rate earthquake ruptures.