Overview
- Mexico’s weather service reports Cold Front No. 25 over the Yucatán driving heavy to torrential rainfall, with 150–250 mm possible in parts of Oaxaca, Veracruz and western Tabasco as it interacts with an upper‑level trough.
- The associated Arctic air mass is producing an intense Norte event along the Gulf coast and Tehuantepec, widespread cold with frost in highlands, and a morning chance of snow or ice on Pico de Orizaba and Cofre de Perote.
- Forecasts list subfreezing minimums in northern and central sierras (down to −10 to −5 °C in the highest ranges) alongside isolated rain chances in central states, while coastal Pacific zones hold hot daytime highs.
- Argentina keeps an orange heat alert for Buenos Aires with highs of 37–39 °C, and forecasters flag isolated storms late Dec. 31 that could disrupt outdoor festivities, with Mendoza under yellow storm alerts that include hail risk.
- The U.S. National Weather Service expects California to transition to a wetter pattern from late Dec. 31 into Jan. 1, with the most active window Wednesday night to Thursday, heavier totals in Southern California, mountain snow in the north and minor coastal flood risk from King Tides near the Bay Area.