This is the “yellow” photo... it didn’t post above.

You can use higher color temp leds for night-time and leave them on during the Western sun time.. 3500 or even 5000k will blue out the yellow. And next time a sheet of drywall painted with your choice will solve this problem before it's allowed to progress to the impossible to change state.

Take the images when the sunlight is not reflecting off the grass.

I have the same challenge. Lots of sun and reflection of greenery outside. It’s tricky. But from the pictures I don’t think it looks so bad, you might want to try it for a few months. You can always repaint later if you really don’t like it.

Strong western afternoon sun will give any white a more yellow tone, and Simply White is a warm, creamy (ie very slightly yellow) toned white although not strongly so to start with - I have it in a north facing room with dark brown floors, and a warm cream/ blue rug, and pale yellow curtains -- it is quite white in there, doesn't appear yellow at all unless I put something that is white white (like printer paper) up against it.

My living room is painted in Navajo White which is distinctly a pale yellow-tan; but in the afternoon when light reflects off the neighbor's red house, the walls look rather pinkish! No color that I could have chosen would defeat that effect.

I think that the advice about using 3000-4000K light bulbs is spot on. Lower color temp bulbs make everything look more yellow.

I am not sure that adding a gray gray to the mix will make the warmth of Simply White less noticeable, it might in fact emphasize it. Classic Gray in some photos looks too gray, but in others seems a nice warm beigey shade that might work very well.

Surrounding the Simply White with somewhat stronger, warm (not cool!) colors will emphasize its white quality. Bringing in furnishings always helps to tone down a wall color. Be careful with your furniture selections to be sure you aren't bringing in clashing tone - the right swatch looks too cool (blue gray) to me.

I don't see yellow. I have simply white on all my trim, crown and ceilings and I think it is a nice bright white, but not stark.

I would wait till it is all done and only then make a decision about changing the wall color, if necessary.

Thanks for the feedback. So I also had this problem in my master bedroom which also faces west. The simply white looked yellow. I repainted with Farrow and Ball Strong White which is a light gray/ Greige. It is such a good color and looks much better. I stupidly thought simply white would work in the great room because it is a much larger space and there are no trees directly outside. I thought the tree leaves were making the master walls look more yellow. Turns out it is the strong, warm western sunlight.

since the lighting is basically the same in the great room and master, I could paint farrow and ball strong white in the great room and hopefully it will look good. However, I would lose the “flow” of having my main living spaces all the same color (Simply white). But they don’t look like the same color anyway because the lighting is so drastically different in different rooms.

It will cost a lot to repaint the great room and I don’t want to jump the gun... but my Navy island, gray sectional and blues don’t seem to work with yellowish walls.

That is a pretty easy paint job, with no floors, fixtures or furniture in the way. I would spend the weekend doing it myself!

If I repaint my walls a light gray like Farrow and Ball Strong White is BM Classic Gray, will that help tone down the yellow in Simply White with the trim, cabinets and ceiling? that seems to be the case in my master bedroom. I still have the Simply White trim and ceiling in there and it basically looks white with the Strong White walls. Both rooms get the same western light.

i just really hope I don’t have to get the cabinets and trim repainted. The walls are much easier.... it is a big room though.

repaint my walls a light gray like Farrow and Ball Strong White is BM Classic Gray, will that help tone down the yellow in Simply White with the trim, cabinets and ceiling? that seems to be the case in my master bedroom. I still have the Simply White trim and ceiling in there and it basically looks white with the Strong White walls. Both rooms get the same western light.

I seems to me that you've answered the question better than any of us could.

Again, repainting with a warm color (not blueish or cool) will likely work best. Unless someone here is familiar (ie has used) either of those colors in combo with Simply white, I'm not sure anyone can answer -- looking at colors over the internet is too unreliable.

my Navy island, gray sectional and blues don’t seem to work with yellowish walls.

Navy is pretty neutral most of the time, IMO, and should work with Simply White. I have some cobalt accent pieces in that Simply White room and they are fine, and my blue/cream rug looks great. It depends, again, on WHICH blues and grays you have. More purplish or cool blue grays will not work, warm grays will. Purplish/lavender blues won't, navy and warmer blues will.

If you are not replacing the sectional (I thought you said your were getting new) and it is a cooler gray that truly doesn't work, then you have to either warm it up/disguise it with throw pillows and afghans, or repaint.

Do you have low e windows? Since these are coated, they can change the apparent color of your walls.