not exactly sure but was it outside all winter? maybe give it epsom salt maybe a type of magnesium deficiency since it is turning yellowish. your new frond coming up looks healthy green but don't know what the lower part looks like yet. keep a close eye on it and see how it looks as it emerges. post pics soon again! -Justin in VB

couldjust be some bud damage due to cold when the leaf was still a spear or forming. If the subsequent leaf does not have that spot, i wouldn't worry about it too much.

The first new leaves in spring will often show this kind of damage. The next few leaves should be normal. It's nothing to worry about, especially if the spear didn't pull. You can see similar damage on one of my windmill palms in this photo from last year after a fairly cold winter (8 degrees):

Could also bee beginning signs of over-watering (if still potted)

Mine had this problem last year but it was summer when it occurred. It could be a nutrient problem or over-watering (mine got a lot of rain last summer) but it doesnt seem to be fatal because now my windmill palm has solid green leaves coming up at a very fast speed (compared to last year). Just make sure it gets plenty of sun and some epsom salt or fertilizer couldnt hurt. If it went through the winter it could be winter damage but if it is then it will definitely grow out of it as the growing season progresses.

Good luck!
-Alex