National Weather Service guidance shows a cold front advancing across the central Rockies this weekend, bringing a sharp drop in temperatures to Denver on May 17 with an expected daily high in the mid-to-upper 60s under increasing cloud cover and northerly flow. This positions the market-implied probability above 87 percent for a peak of 71°F or lower, consistent with model consensus from the GFS and NAM ensembles projecting 500-mb heights falling 40–60 meters behind the front and reduced insolation at the city’s 5,280-foot elevation. Recent warming earlier in the week has given way to this rapid cooling, with historical May analogs indicating such post-frontal days rarely exceed 70°F when upslope winds and moisture return. Traders will watch the next NWS update and any shifts in the surface pressure gradient for signs of warmer downslope winds that could push readings into the low 70s.