Since I moved to south Florida, a couple of years ago, I've never experienced anything like that from my beloved 2013 . It always cooled reliably and fast at any speed.. it's not normal.

 

The refrigerant (a.k.a. Freon) in any A/C system is in a 'closed loop' and should never (under any circumstances) leak where additional refrigerant needs to be added. This applies to a refrigerator, freezer, etc. If the refrigerant is low - then there is a leak, which is highly unusual.

I live in Dallas where it commonly gets over 100°, and the A/C in the GS 350 has always done a wonderful job of cooling and removing the humidity to a comfortable level.

 

I notice this too but have always thought it was normal. If you accelerate hard enough the ac will blow warm, its going to give more power to the engine and kick off. I was coming back from lunch and did a launch and hit redline a few times and it always does this. I'm in Texas too, I figured it was normal. AC blows fine unless I'm accelerating hard like that which is frequent

 

I believe this is normal too. Worked that way on several different cars of mine in the past (not just Lexus). I don't think it HAS to be WOT, just really heavy load.

I have noticed it in my car too, but not very often. Now that could be because I don't normally have a lead foot, but either way I'll be its fine. Perhaps you just notice it more since it is so hot.

 

It is normal operation for every vehicle nowadays.

 

If your cabin filter is really dirty, it may interfere with your A/C, Go to an oil change place if you can't do it yourself and have them check it. This resolved all my issues with my A/C in my GX 470.

 

If your cabin filter is really dirty and needs to be replaced, this may be part of the problem. If you can't do it yourself, go to an oil change place and have them pull it. Replace if needed. I was also having A/C issues where it kept shutting off and I had to press the A/C buttton over and over. Lexus in Colorado said I needed a new compressor ($3K) and never checked my cabin filter...it ended up being the cabin filter for $25. Easy fix!

 

The AC system has seals and gaskets that can leak/expand/contract especially during extreme temperatures that causes Freon to slowly escape. Those DIY refrigerant refill cans are pretty big sellers because of this. My GS430 was not blowing very cold air on really hot days one summer and the refrigerant refill fixed the problem, it was a little low.

 

That VERY RARELY happens in Toyota/Lexus vehicles. And, it never should happen. Refrigerant seals should never leak even after more than a decade. Why did you not have the leak fixed on your GS 430 instead of just adding more refrigerant knowing you had a leak and that the refrigerant would leak out again?

Years ago Ford had the worse reputation for their A/C refrigerant seals to leak.

 

No, you really don't. There's a reason real estate is cheaper where it's hot. It's easier to warm up than it is to cool off when it's 102 outside with a heat index of 116 like last week.

 

I am one of those people who loves it when it gets into the low 100s. It's been years since I've lived in that kind of climate and I really miss it. It's supposed to hit 100 here later in the week, which is very rare for Seattle. People are dreading it but I am excited!

 

Sounds like the heat has gotten to your head already lol. You love it!? I can’t say the same. High temperatures and low humidity is ok, but high humidity here in S Fla is ridiculous.

 

Yes, high temperatures combined with high humidity is tough. I can handle that but in more limited doses. I've spent time in Florida in the spring and summer and the humidity is intense.

 

I did not have the leak fixed because I did not want my bank account drained by the dealership and figured if a $30 refill can worked why not give it a try as it works for so many other people, my seals did leak after more then a decade along with millions of other peoples vehicles who have had the same issue. It is not that rare and Toyota/Lexus are not immune to low refrigerant from leaks over time, look how many people buy those refrigerant refills and how popular they are. If there was a slight leak the refill normally has a mild sealer and any leak would be a very very slow one as it took over 10 years for the refrigerant to get low enough to effect the AC temperature so it would likely last another 10 years or so and there would be no reason to have a shop try to fix the leak. Once I added some refrigerant it blew ice cold air again for 2 or 3 more years with no issues until my car was totaled.

 

Since you say you never drive in eco mode? assuming just like me, every time its set to sport+, sometime sport. Never care for eco or normal.
With that said, sport(+) mode commands the computer for performance. So with A/C compressor on, it is taking a minor load on engine when engaged.
When you floor it, certain parameter are met, the computer shut off compressors for performance sake. So if you have AC in full blast, compressor will disengage. of course the blower will still blow.. Not 100% sure, but you can test on normal mode vs sport for your curiosity.

Also, if you have a leak and never found out where it's leaking, it will continue to leak regardless how many time you recharge the freon yourself.
Under and over-charging will affect cooling system. If theres a leak, expect air to enter your a/c system thus further causing a/c concern.
Lack of a/c operation, hardens the seals and cause leakage. A/c condenser is in front of the radiator (behind front bumper), a small rock chip will cause a leak. A/c fan not working etc.

just my opinion =D