The VW eGolf manual does indeed have warnings about a few conditions which can reduce battery life:
"Frequent and consecutive high-voltage charging (including DC charging) can permanently decrease the capacity of the high-voltage battery. Battery capacity will decrease if you frequently and consecutively charge your vehicle at a DC charging station. Therefore always alternate high-voltage charging (including DC charging) and low-voltage charging. For example, you can charge your vehicle overhight at an AC charging station or use an AC Wallbox if the vehicle was charged at a DC charging station during the day."
"Frequent and consecutive charging of the high-voltage batter when the charge level is above 98% can also decrease the capacity of the high-voltage battery. Make sure the charge level is below 98% when you start the charging process."
"The high-voltage battery can be damaged and the capacity can be decreased when the vehicle is parked for longer than 24 hours when the ambient temperature is higher than 119 F (48 C). Always make sure that the high-voltage battery is not exposed to temperatures above 118 F (48 C) for a long time)."
You park that car over hot black top in Texas from May through September in the Walmart parking lot that has baked in the sun, and the temp
(all the above are from Page 250 in my copy of the 2015 eGolf manual.)
All the above warnings relating to reducing battery capacity are on the charging and storage side - I haven't seen anywhere in the manual where it warns against any otherwise-permitted behavior on the discharge (driving) end of things; so unlike what others may have implied, VW does not have any warnings against driving at 65, 75, or even 85 mph - it shouldn't permanently reduce battery capacity. Driving quickly *will* consume more kWH/mile of course, so it will mean that when you do so you won't get as many miles before your next charge, but that's just temporary until the next charge/drive cycle.
I was interested and encouraged to see reports of the eGolf's power meter indicating reduced maximum power when the battery temperature got too high - I would speculate that this is the reason that VW doesn't warn against high-speed driving with respect to harming the battery even in warmer climates - the car itself will reduce power consumption to keep the battery within operating limits. I'm guessing that this is due to the "Battery Management Unit" described by the VW press release published at the link JoulesThief posted earlier (http://www.autoblog.com/2014/03/31/vw-e-golf-will-not-have-active-cooling-system-lithium-battery):
"As it relates to battery temperature, VW has developed a Battery Management Unit with an intelligent thermal control that allows the pack to remain within an optimal temperature window, helping to maintain performance and range in a variety of temperatures. This system allows the e-Golf to operate, even in more extreme temperatures, without the need of a cooling system and without dramatic impacts in performance based on testing."
So from what I've read on this forum and in the manual, if it was me, I'd be concerned primarily with being able to locate a local dealer who would be willing and competent to service your eGolf; secondarily perhaps I might worry a little about the 118 degree temperatures, but a quick check of Weather Underground history for Dallas (for example) shows a high in July of about 102 degrees, combined with overnight temperatures below 90 - in the heat of summer. Short of parking your car in a greenhouse, I'd think you'd be hard pressed to find a place that gets over 118 F except briefly and only occasionally, much less for an entire 24 hours period.
Of course I'd also heed the warnings about "frequent and consecutive fast charging", but that's the case whether you're in Texas or in New England, or anywhere else for that matter.
