Good questions . . .
(1) We post the low for the 24-hour period of the calendar day on the website.
(2) On something like 90% of the days, the low actually occurs sometime closer to sunrise . . . and to me, that is the "morning" of the next day, and not the "overnight."
(3) So, on our graphics, for most days, the posted low represents the early morning temperature and the high is for the afternoon.
True . . . several other sources still say "overnight low," and some will even put the low on today's graphic (representing tonight) rather than on tomorrow's graphic . . . in effect, showing the low on the wrong calendar day. I see that one of our competitors has changed their practice recently to be more reflective our our approach.
In my mind, saying "tonight's low" is misleading . . . and even explains why so many people think the "coolest" part of the day is near midnight rather than near sunrise.
Whether you're planning for the kids' dress for the bus, or just getting ready for your own morning commute . . . posting the low as tomorrow's wake-up temperature is much closer to the "truth" for the vast majority of days.
Yes, it is semantics, but to me, stating "tomorrow morning's Low" is much more representative than saying "tonight's low."
Thanks for the question!
WAFB Storm Team