What is causing the rains in CDMX?
Precipitation in CDMX is due to the interaction of several factors:
-Polar troughs at high levels, which generate atmospheric instability.
-Low pressure channels over the center of the country, which favor the formation of clouds.
-Constant entry of humidity from the Pacific, the Gulf of Mexico and the Caribbean Sea.
-Polar jet currents, which drive these systems towards the center of the territory.
Although cold fronts are mainly associated with low temperatures, in this case they are also contributing to the presence of rain, by interacting with humid air and systems at altitude.
This afternoon a warm atmosphere is expected, skies mostly #cloudy with conditions for #rains dispersed mainly in the south and west of the city. In the early morning and tomorrow the atmosphere is expected to be very #cold in the south.
It is recommended to be attentive to the Early Warning System of… pic.twitter.com/4PEv9Ww4Zy
— Secretariat of Comprehensive Risk Management and PC (@SGIRPC_CDMX)
December 18, 2025
What is expected in CDMX from December 19 to 22?
According to the SMN’s extended 96-hour forecast, Mexico City will remain under conditions of light rain to isolated showers, mainly in the afternoons and nights.
Friday, December 19 to Monday, December 22:
Isolated rains (0.1 to 5 mm) are expected in CDMX.
Possible electric shocks in some events.
Cold atmosphere in the morning and night, with warmer temperatures in the afternoon.
Although the heaviest rains will be concentrated in southeastern states such as Chiapas, Veracruz, Tabasco and Oaxaca, the Valley of Mexico will continue to receive enough moisture to maintain unstable conditions.
Will it be cold in the capital?
Yes. During this period the cold to very cold environment will continue on the Central Table:
Early mornings with low temperatures, especially in high areas of the Valley of Mexico.
Risk of frost in nearby regions of the State of Mexico.
Lower thermal sensation due to humidity and cloudiness.
What risks do these rains imply?
Although heavy rains are not expected in the capital, authorities warn of:
Ponding in areas with poor drainage.
Slower traffic and slippery pavement.
Possible fall of branches or signs due to moderate gusts of wind.
Increased sensation of cold, which can affect children and older adults.
Recommendations
Civil Protection and the SMN recommend:
Check the daily forecast before leaving.
Drive with caution during afternoon rain.
Dress appropriately and avoid sudden changes in temperature.
Respond to official warnings in the event of rain or thermal decline.
In summary, the December rains in CDMX are not extraordinary, but they are atypical for the season. They are caused by the combination of cold fronts, humidity and systems at altitude, and will continue to occur intermittently until December 22, along with cold mornings and mild afternoons.
