Never had a problem in 2 years...the kids in back of my car actually complain about it being too cold. Using the floor vents actually gets air driectly to the back seats as in most small cars.
I apologize if someone already mentioned this in the thread, but if you do have difficulties maintaining cooling comfort, take the car out of "Eco" mode, as that mode de-tunes the a/c (this is also in the manual ).
In hot weather, if one has the Torque OBD Android app, you can set the HV battery intake fan to full speed (level 6), this will draw cool air from front to the rear, because HV battery air gets exhausted to outside. To further boost the front to rear cool air movement in the first 5-10 min of driving, take HVAC out of recirculate mode. You can then set back to recirculate for economy once the rear occupants have cooled down. Also you can then set the HV battery fan back to normal (you don't want to shorten the life of this fan) It's usually in the first few minutes of the drive when the rear passengers need maximum cooling, if the car has been sitting in the heat. It goes without saying to use a windscreen shade and if you can buy tinted raingaurds to mount above the 4 side windows, they will provide further shade from the midday sun, as well as allowing you to leave all 4 windows open a few inches. And finally if you can get a rear hatch window shade with angled slits that block the vertical sun, but allow you to see through it horizontally. Combined with a white color on the car, your Prius will be prepared for the hottest mother nature can throw at it.
As indicated in my post above, the Prius v AC is stronger than Gen2 and works very well. Living in South Texas and owning a 2012 v and a 2008 Gen2, I know this for a fact. However if you leave the car in the direct sun all day, I recommend opening one or two windows for the first 1/2 mile or so to blow out the 140F air. Then you only have ambient air to cool. Recirculate will cool it faster, then go to other modes when it gets cool if desired. As indicated above ECO mode will drop out the AC compressor at times so if you want it cool fast you could go to Normal drive mode.
For me the AC works best for the rear folks when not using the floor setting - my grandchildren complain they get no cooling from that. The only good things I have to say about the cooling in the Prius v are that 1. it is quick to work, thanks to that electric compressor and 2. I love the magical button that when pressed delivers a one-minute blast of the coldest air to the driver and front passenger's face! Then it returns to presets. Just a great idea. Overall I think the climate control is not legendary in this car. I'm in Canada and need the whole range of cold to hot. This system doesn't seem very flexible, you get cold or hot, but not the fine distinctions. Also it seems like it is either blowing right at you or ineffective - there is no easy way to have an adjustable 'ambient' temperature without drafts (or hot air in heat mode) blowing at you.
