Recent National Weather Service model runs project San Francisco afternoon highs in the upper 60s to low 70s on May 18, driven by building high pressure that weakens the typical marine layer and allows warmer offshore flow to dominate. These conditions align with late-spring climatology, when seasonal averages near 65°F frequently climb higher under similar setups. Ensemble guidance shows limited spread below 68°F, supporting the market's strong consensus. A sudden strengthening of the onshore breeze or earlier marine intrusion could still cap readings in the mid-60s, though current observations and guidance indicate low likelihood of such a shift before the period ends.