São Paulo is 2 hours ahead of Houston
Best overlap: 8:00 AM to 4:00 PM in Houston is 10:00 AM to 6:00 PM in São Paulo.
Plan around 8:00 AM to 4:00 PM in Houston, which is 10:00 AM to 6:00 PM in São Paulo, to catch everyone during office hours. São Paulo is 2 hours ahead of Houston, but with 8 hours of common ground you can hold morning or afternoon meetings without anyone working odd hours. For part of the year the maths changes: Houston observes daylight saving, São Paulo does not, shifting the overlap by an hour.