I don't want to compare against Djokovic or any other player, but I actually have Federer's full list of day matches played in his career at the AO. It's 45 in total (9 since 2014). Of course no-one plays SF or Final during the day.
Hence, the maximum possible number of day matches one can play in a given tournament is 5 (R1 - QF). One 1 occasion (2011), Federer played 4 day matches out of a possible 5. On 9 occasions, he played 3 day matches out of a possible 5.
In 16 of these 45 match days, the temperature went above 40C (as per the Aus Government Bureau of Meteorology data). From these 16, 9 of those reported max temperatures above 43C, resulting in on court afternoon temperatures higher than 50C.
2017 R2 vs Rubin
2016 QF vs Berdych
2016 R3 vs Dimitrov
2016 R2 vs Dolgopolov
2015 R3 vs Seppi
2015 R2 vs Bolelli
2014 R3 vs Gabashvili
2014 R2 vs Kavcic
2014 R1 vs Duckworth
2013 R1 vs Paire
2012 QF vs Del Potro
2012 R3 vs Karlovic
2011 QF vs Wawrinka
2011 R4 vs Robredo
2011 R3 vs Malisse
2011 R1 vs Lacko
2010 QF vs Davydenko
2010 R3 vs Montanes
2010 R1 vs Andreev
2009 R4 vs Berdych
2009 R2 vs Korolev
2008 R4 vs Berdych
2008 R3 vs Tipsarevic
2008 R2 vs Santoro
2007 R2 vs Bjorkman
2007 R1 vs Phau
2006 R2 vs Mayer
2006 R1 vs Istomin
2005 R4 vs Baghdatis
2005 R3 vs Nieminen
2005 R1 vs Santoro
2004 R3 vs Reid
2004 R2 vs Morrison
2004 R1 vs Bogomolov Jr
2003 R3 vs Vinciguerra
2003 R2 vs Burgsmuller
2003 R1 vs Saretta
2002 R3 vs Schuttler
2002 R1 vs Chang
2001 R3 vs Clement
2001 R2 vs Escude
2001 R1 vs di Pasquale
2000 R3 vs Clement
2000 R2 vs Kroslak
2000 R1 vs Chang