The Nexus was still a rather new and shiny place, and Hohenheim had sated his curiosity for the modern inventions which were in the apartment where he was temporarily lodged.
Having done so, he took it upon himself to explore a bit, and the Sign was a remarkable curiosity; so much, in fact that he did not immediately notice who was seated there. This was interesting. He was rather certain this was not the homunculus from his own world.
His attire was still quite far out of date from what would be considered a 'current' time period for many known versions of Amestris, along with his bearing and manner of speech.
"The summer was generally a period of time when many balls and festivals were held throughout the duchy, first around the time of the Summer Solstice, then later on again approaching autumn. While a great many are also held over the winter season, the summer season has the advantage of not being quite so terribly muddy."