I looked it up in the Liturgy of the Hours, Vol. III, The Proper of Saints. His feast day was set on January 28th, the day his body was transferred to Toulouse in 1369.
In the General Roman Calendar of 1962, , Aquinas was commemorated on 7 March, the day of death. However, in the General Roman Calendar of 1969, his date was changed to January 28th even though the norm in the Roman Catholic Church is to remember saints on the day of their death.