A persistent weather system is delivering a high probability of rain showers and thunderstorms to Northern New Mexico, bringing cool daytime temperatures and accumulating precipitation to mountain zones including Chama and Los Alamos through the upcoming week according to the National Weather Service forecast issued on September 28, 2026.
Chama Weather and Mountain Precipitation Outlook
Forecasters report that the Tusas Mountains region, including the city of Chama, faces a near-100 percent chance of precipitation early in the week. Monday brings a 70 percent chance of rain showers and afternoon thunderstorms, with south winds sustaining speeds between 15 and 20 mph. Daytime highs are expected to reach the upper 50s before dropping into the lower 50s by afternoon.
Precipitation chances peak near 100 percent on Monday night and Tuesday, accompanied by the potential for heavy rainfall during storms. Temperatures will continue a downward trend, bottoming out in the mid-40s by Tuesday afternoon. Northeast winds around 15 mph are projected for Tuesday evening as the system lingers over the region, maintaining a 90 percent chance of rain before tapering off toward midweek.
Los Alamos and Jemez Mountains Forecast
In the Jemez Mountains, including Los Alamos, conditions closely mirror those in the northern sector. Monday opens with a 50 percent chance of showers and thunderstorms by the afternoon, bringing high temperatures to the mid-60s. South winds will average around 15 mph.
Precipitation chances escalate to near 100 percent on Monday night, with thunderstorms potentially producing heavy rainfall after midnight. Lows will settle in the upper 40s. Tuesday brings continuous showers and a slight chance of thunderstorms, with temperatures holding steady in the lower 50s before cooler air moves in for Wednesday, bringing snow-level transitions down to higher elevations as lows dip into the upper 30s by Wednesday night.
Mid-Week Clearing Trend and Weekend Outlook
As the low-pressure system exits the state, conditions across both the Tusas and Jemez mountain zones will dry out significantly. Thursday through Sunday will feature mostly clear skies and gradual warming. Daytime highs are expected to recover into the mid-50s on Thursday, climbing to the mid-70s by the weekend. Overnight lows will remain chilly, stabilizing in the upper 30s to mid-40s across Rio Arriba and Los Alamos counties.
