Over 640 are killed after a magnitude 6.4 earthquake strikes the Mexican states Puebla and Veracruz.

A moment magnitude 6.3–6.4 earthquake affected southeastern Mexico, in the states of Puebla and Veracruz, on 3 January 1920 at 22:25 local time. A maximum Mercalli-Cancani intensity of XI–XII (Extreme) was recorded in the epicenter, between Chilchotla and Patlanalán. While estimates of the death toll vary across different sources, ranging from 648 to 4,000 fatalities, it is the second deadliest earthquake in Mexico, behind another earthquake in 1985 that killed more than 9,000 people. Many people died from mudslides that swept through settlements along the Huitzilapa and Pescado rivers. The cost of damage was estimated at US$25,000,000. The towns of Patlanalá, Barranca Grande, Cosautlán, Quimixtlán, Teocelo and Xalapa were severely affected, as many buildings were damaged or destroyed.

January 3 is the third day of the year in the Gregorian calendar; 362 days remain until the end of the year.