Some actual experience:
My Leaf is kept essentially every night in a detached garage. It has been a predictably hot summer in Houston, TX (90 -95 degree afternoons - 100's today
). Most charging is done overnight, with 3.3 kw power and 80% limit. LeafSpy temps in the morning are in the high 80's to low 90's. The garage floor temp is around 88 degrees (IR gun). Driveway temps in afternoon sun (concrete) are 125 degrees+.
I park in a garage at work and the usual temps when I get back home are in the mid to high 90's. Never hit 100 yet. I put about 6000 miles per year on the car and use it almost every day. This "cycle" has been documented for a couple of weeks now. I'm interested in what happens this winter - will keep taking the readings.
The surprise to me is that the heat capacitance (in my situation) seems to keep the battery at fairly constant temps - and it seems to cool fairly well at night even with LII charging. I'd bet that some QC's and/or parking in full sun (on black tar) would fairly rapidly elevate these temperature ranges. The temp bars have stayed at 6 - never moved since start of summer.
2012 Leaf SL; 43,000 miles. Battery replaced November 1st, 2016.