Latest National Weather Service ensemble forecasts for May 18 project a daytime high in New York City between 78–82 °F, driven by southwesterly flow ahead of a weak frontal boundary and modest mid-level ridging that limits strong warm advection. This range accounts for the closely matched market probabilities on 78–79 °F, 80–81 °F, and 82–83 °F, as differing model solutions on boundary-layer mixing and cloud cover produce a 3–4 °F spread in maximum temperature. Historical May climatology places the 1991–2020 average high near 73 °F, so the current setup represents a modest positive anomaly that traders are pricing against the risk of slower warming if marine air intrudes earlier than modeled. Updated guidance from the 12Z and 18Z runs, along with any revised surface observations from Central Park and LaGuardia, will further refine these probabilities ahead of resolution.