Mexico City Mayor Marcelo Ebrard said the lifeless bodies of four people had been found on city streets since Wednesday, including one person with pneumonia. Officials were investigating whether the other three deaths were also caused by the weather.
Another man was found dead of pneumonia in a vacant lot in Guadalajara.
Temperatures dropped to -3C in central Puebla state, where residents woke to snow-covered mountains and authorities opened more than 100 shelters.Snow is not uncommon at very high altitudes in Mexico during the winter, but this week's cold front brought frost and light snow to towns that normally don't see such weather. In the capital, residents accustomed to 30C afternoons bundled up in temperatures as low as 0.