I have a 2004 Honda Civic ex and I have a issue with the a/c when it’s 90+ degrees outside the a/c blows hot air I checked to see if the a/c clutch is engaged and it was. I check the fans and they were both on everything is on and seems ok but When I checked the refrigerant Level the needle went in red (warning) then when the weather cools down a little bit the a/c would kick on just a tiny bit & I check the level and it went in the yellow (warning) when it gets dark and is cool outside the a/c works perfect blows ice cold & when I check the level it’s in blue (meaning it’s full of refrigerant) not sure what’s going on with the a/c jumping to warning and back to normal blowing hot air then cold air?
I had a related issue, the car would stop the AC in hot weather. The temp gauge on the dash would start to climb a little. I used an OBD adapter and saw that the coolant was exceeding 100C.
After some time, I found the issue. A lot of dried grass and dirt between the AC radiator and the engine radiator. This put a strain on the cooling system in hot weather.
Since its a simple job, check this first, before doing any other expensive check-ups
You probably have a very inexpensive gage, which is not super accurate.
There are two possibilities.
Someone added the wrong kind of refrigerant; the system needs to be cleaned and replace with the correct refrigerant (assuming it is available)
It just needs a bit more of the right type of refrigerant for the system
There are 2 different types of air conditioning refrigerant currently used in residential cooling systems. R-22, commonly referred to a Freon and R410A, a blend considered to be more environmentally friendly, sometimes called Puron. Source