Yellowing can be caused by many things.

Some of the common causes are lack of nitrogen, lack of water, lack of iron, too much water, high pH, going into dormancy, . . .

If I remember correctly (and judging by your name) you're in the east, so high pH isn't likely to be a culprit. Depending on how much water you've been getting, that could be an issue. Or it could be that the lawn is starting to go into winter dormancy (how cold has it been?).

You say water has been steady. How steady? Too much water can be a problem.

I am in New Jersey. The weather has been relatively warm thus far. In fact, today is t-shirt weather. I was watering a lot during my overseeding in September. I haven't watered in a week because we have had some rain.

I am wondering if this was caused by my compost tea. I made/sprayed my first batch a couple weeks ago. I wonder if I didn't aerate it enough and therefore got some funky fungi/bacteria growing.

I have some corn meal gluten that I want to get rid of, so maybe I will spread that today and see what happens. Maybe it will give it enough of a nitrogen boost over the next few weeks.

Rutgers, my (long distance) diagnosis is fertility. Nitrogen starvation.

I'm a huge fan of Milorganite, I love the stuff, but it's a 6-2-0. That's great, for June, July, and August, as it won't burn the lawn and will provide some nitrogen. It's also a pat answer, for newbies to the lawn forum, whose question usually amounts to 'Gee my lawn looks like heck', much as a doctor would say 'take two aspirin, and call me in the morning'.

A lawn needs nitrogen, and most people just don't give it enough nitrogen. It's that simple, when you're dealing with those folks (you are not those folks: bear with me). The old (and I don't know where this started, nor how long ago, but it's wrong) doctrine of 'fertilize once in the fall, and maybe once in the spring' just DOES NOT hack it these days. More nitrogen, and at more frequent intervals, is needed, desperately, or your lawn will look like an elementary school yard with it's ruts, tracks, scuffs, and bare spots. And Milorganite (6-2-0) is just not enough nitrogen. You need a big-first-number fertilizer, like a 20, or a 24, or a 30.

For a lawn. And you don't have a lawn. You have brand new seedlings, that are pushing up, spreading out, putting out tillers, rhizones, and a heck of a lot of green material (above ground) and brown material (below ground) all from one tiny dot that was, six weeks ago, only a seed. They're working their butts off, aren't they? They need food to get it done. And you haven't given them enough food.

Add to that, you probably didn't pick some ol' junk grass, you went with a newer variety, more dense, better color, and probably a 'heavy feeder'. Heavy feeder? Eating what, may I ask? All of the nitrogen source on that lawn has already been used up, and the food's gone.

With the food gone, that grass is going to stop working (which we don't want), going to stop developing or 'establishing' dominance over that soil, and going to start turning pale, and then yellowing.

Get some nitrogen on that lawn today, would be my prescription. And plan on adding more.

rutgers1, ....fertilized regularly...mainly organic. If there is a deficiency, it is likely to be the one(s) missing, (or in short supply) from the product that you have been using. ('Milorganite' has not enough potassium for this element to be included on the label). ....Water has been steady and T-shirt temperatures suggest that 'climate' has been agreeable. If the yellowing is associated with the new leaves, you might be witnessing the symptom of too much water/too little air in the soil. Probe the soil to find out.
I have no experience with the application of "teas" but I doubt that they would cause adverse symptoms if properly used.
If the yellowing is associated with the more mature leaves, it would indicate that the plant is drawing a mobile element from the older leaves to supply the growing tissue. Potassium comes to mind first.
If the yellowing were evenly distributed over the whole plant, low nitrogen would be a probable cause. The nitrogen in truly organic fertilizers is slow release and depends upon temperature and micro organisms for best results. I would not be surprised if the activity slows down significantly as the temperature drops away from 80 degrees. But even if the yellowing were sympotamatic of nitrogen deficiency, one cannot discount iron, magnesium and manganese as "elements of interest". They are significant components of the chlorophyll molecule and can green up a lawn without resulting in increased growth. I would discourage increasing growth at this time.
But I digress! If there is no soil water/air issue, I think that the turf is showing a deficiency of potassium and/or some minor elements. I would apply a palm-type fertilizer which would supply low nitrogen, additional iron, magnesium and other minor elements. Try a supplier who caters to the commercial operators. If you are not one of them expect to pay a little more. It will be worth it.

I would second the suggestion of too much water. If you watered alot to get an overseed going, then got rain, it just may need to dry out and get more oxygen into the root zone. That just takes some time.

Thanks for the responses. What is palm-type fertilizer?

Around here we're having some yellowing, both myself and my neighbors. I spoke to the guys at Lesco and they agreed that it was a rust that we get around here this time of year. The temps have been cooler with a lot of rain. So I purchased a fungicide and applied that today. I also used a high nitrogen fertilizer about 2 weeks ago.

rutgers1, Palm-type fertilizers have an analysis where the first and last numbers (nitrogen and potassium) are about the same (10 to 14), the nitrogen is slow-release and the iron, magnesium (and manganese, sometimes) percentages are higher than in a turf fertilizer.