McLaren-Mercedes' English driver moved back to the principality in February after a year in Guernsey and has spent much of his time cycling the city's sun-kissed roads, many of which annually transform into the sport's most challenging street circuit.
Button finished ahead of a Lotus driven by the Frenchman Romain Grosjean, but a surprise spell of rain deemed the session wasted.
With tomorrow traditionally a rest day in Monaco, the next opportunity the drivers will get to acquaint themselves with the weaving, narrow track will be Saturday.
"We were quickest, but we were one of the only guys to do a lap on the super softs," Button said.
"I don't think it's massively quick, but it feels OK. There is a lot of room for improvements. It's not that we have a problem and don't know where to go. We know what direction to go.
"The cars that look very fast to me are the Lotuses." Grosjean is competing in Monaco for the first time in a F1 car and is hoping to become the sixth driver in as many races to win a grand prix in 2012.
The 26 year old looked at ease and, finishing second fastest in the morning and, even when the drizzle began later in the day, performed largely unhindered.
"The car is suiting the track pretty well and I love Monaco. The car was looking good this morning and this afternoon - we are working in a good direction.
"Unfortunately, it was wet in the afternoon and we couldn't do the programme we wanted, but as we have a good baseline it shouldn't be such a big deal. We are looking good in both conditions."
The Ferrari pair of Felipe Massa and Fernando Alonso finished third and fourth fastest.
Massa had said earlier in the week he hoped Sunday could prove the start of a resurgence in form following a series of poor performances and yesterday he appeared reserved but pleased.
"Sure, there is still plenty of work to do to fine tune all the set-up details, but we have an extra day to think about what to do to improve in this area," he said.
"It's hard to make predictions about qualifying and even more so for the race, but definitely we can say the first day of free practice can be considered a positive one."
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