Is it possible to determine what daytime the Chicxulub impactor striked the Earth 66 mya? Was it day or night, what was the current phase of the Moon etc.? Can sediments, rhytmites or something else hold this information?
Given that the uncertainty in deltaT, the difference between the uniform dynamical time needed to predict the positions of the Sun and the Moon and civil (solar) time was already 4.5 hours by year -4000 (https://eclipse.gsfc.nasa.gov/SEcat5/uncertainty.html), then I would say by 65 million years ago we would have no idea of which way the Earth was facing at the time. Unless the dinosaurs left eclipse records that would let us calibrate the much faster spinning Earth back then, we would have no means to work out what time of day the impact happened.
That's the best scientific indicator that we have regarding daytime: it was significantly more likely to occur either side of dawn.
Specific scientific evidence would have to come in the form of biochemical markers from fossils, which is possible but practically impossible. One of the few fossils from the KT boundary was found 13cm below it, a Ceratopsian dinosaur horn, about a year previous, and we'd need multiple fossils from the same day.
Difficult to recover data from a 10 billion Hiroshima explosions that happened 65,500,000 years ago.