When is the rainy season expected to end in Mexico and the dog days to begin?

Every year, Mexico experiences an intense rainy season that, in addition to nourishing ecosystems, poses considerable risks to the population due to the presence of tropical cyclones, storms, landslides, and floods . This period, closely linked to meteorological phenomena in the Pacific and Atlantic Oceans , extends from mid-May to late November and culminates with an opposite but equally significant phenomenon: the canícula (heat wave ).

According to information from the National Meteorological Service (SMN) and the National Center for Disaster Prevention (CENAPRED) , the rainy season in Mexico begins on May 15 in the Pacific and on June 1 in the Atlantic , ending in both basins on November 30. During this period, the country remains under constant surveillance by Civil Protection , due to the possibility of severe weather events.

By 2025 , the National Meteorological Service (SMN) forecasts the formation of between 16 and 20 tropical cyclones in the Pacific and 13 to 17 in the Atlantic . Although not all of these systems will make landfall, at least five are estimated to directly impact Mexican territory: three from the Pacific and two from the Atlantic.

The months of May and June could see increased rainfall , according to data from the National Water Commission (Conagua) , making it necessary to redouble precautions in communities located in risk zones . Emergency backpacks, family civil protection plans, and heeding weather warnings are key measures to deal with this period of high vulnerability.

Once the peak rainfall is over, Mexico enters the so-called dog days , a climatic phenomenon characterized by a temporary drop in precipitation and a significant rise in temperature . This episode typically begins during the last half of July and lasts for about 40 days , although its duration and intensity can vary slightly each year.

During the dog days, the sky remains mostly clear and relative humidity decreases , a sharp contrast to the rest of the summer. This phenomenon is caused by a combination of atmospheric factors that inhibit the formation of rain, generating extreme heat conditions in specific regions of the country.

The states most vulnerable during the dog days are those located in the southeast and east of the country , where the temperature increase can be most severe. States such as Veracruz, Tabasco, Tamaulipas, Nuevo León, San Luis Potosí, Colima, Michoacán, Guerrero, Oaxaca, and Chiapas tend to experience the most noticeable effects, with temperatures reaching over 40°C in some locations.

In contrast, central and northern regions such as Mexico City, Zacatecas, Aguascalientes, Coahuila, and Querétaro have a lower incidence of this phenomenon, although they are not completely exempt from high heat.

During this period, it is essential to take measures to prevent heat stroke , stay well hydrated , avoid prolonged exposure to the sun , and take special care of children, the elderly, and pets .

Both the rainy season and the dog days are part of a climate cycle that can vary annually due to factors such as El Niño, La Niña , and global climate change . For this reason, meteorological authorities insist that the population stay informed through official and reliable sources, such as the SMN (National Meteorological Service), CENAPRED (National Commission for National Meteorological Services), and Civil Protection .

Timely preparation for extreme weather events can save lives and reduce property damage . Furthermore, understanding regional climate patterns allows rural, agricultural, and urban communities to better plan their productive and public health activities during the summer.

Summer in Mexico is marked by two contrasting phenomena: an intense rainy season that can lead to dangerous cyclones, and the subsequent canícula (heat wave ), which imposes a wave of extreme heat and dryness . Both events require attention and preparation , especially in historically vulnerable areas. With the forecast for more intense rainfall in May and June, and the possible start of the canícula (heat wave) in the second half of July, being informed and prepared will be crucial to facing the climate challenges of 2025.