I know the two temperatures for each day on the weather app indicate the high and low. My question is, what time does each "day" begin/end? At midnight or some other time? The highs and lows often don't seem to "fit" with a midnight begin/end for each day, but I'm not sure.

If measured midnight to midnight, then I'm confused. Right now the weather app predicts (for Durham, NC) that it will be 19 degrees tomorrow morning at 6AM according to the HOURLY prediction, but the DAILY low for tomorrow is listed as 26 degrees. This doesn't jive. Anyone know the reason?

  • Highs and lows are measured as the maximum & minimum expected for any 24 hour period, midnight to midnight. ALL weather forecasting is done this way. Jan 21, 2019 at 13:54
  • @SteveChambers Daniil Manokhin's answer contradicts you. His/her source for the iPhone specifically is questionable IMO, but the fact that the term "Meteorological Day" exists suggests that not all forecasting is done midnight to midnight. Jan 21, 2019 at 16:03
  • @Wowfunhappy also see discussions.apple.com/thread/4808505
    – user310476
    Jan 21, 2019 at 16:11

1 Answer 1


If is believed thy the iPhone weather.app uses a Meteorological Day.

This is rightly sunrise to sunrise.

This is roughly sunrise to sunrise and meant to be more useful for people who are looking ahead and thinking "what's the high today and the low tonight?"

Check the low for the following morning (around 4 or 5am), that's probably where you'll find it.


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