Except today, at my latitude (40 50.7' N), there are 12 hours and 9 minutes of sunlight. Thursday has 12 hours, 1 minute, and Friday has 11 hours 58 minutes. Seems to me the equinox should be sometime during Thursday or Friday
Edit: It's a matter of definition. Equi
lux is what I am thinking of, where periods of light and dark are equal. From wikipedia:
The equinox is not exactly the same as the day when period of daytime and night are of equal length for two reasons. Firstly, sunrise, which begins daytime, occurs when the top of the Sun's disk rises above the eastern horizon. At that instant, the disk's center is still below the horizon. Secondly, Earth's atmosphere refracts sunlight. As a result, an observer sees daylight before the first glimpse of the Sun's disk above the horizon. To avoid this ambiguity, the word equilux is sometimes used to mean a day on which the periods of daylight and night are equal.
Now that I've solved that, Happy Equinox!