Adding of 1 day to sunrise and sunset times happens too early about solar

[guidove]

I found a workaround that works for me for the moment. I basically strip the date component from the dates and only use the time components. It's not that precise as it could compare the current date/time to the sunrise & sunset time of tomorrow, but that's ok for my usage (I use it to switch App color theme at sunset / sunrise).

It's not fail safe as it doesn't work for very northern / very southern locations where the sunset is after midnight / sunrise if before midnight or even doesn't set or rise at all, so a fix or other workaround would be appreciated.

Here it is:

    public var isDaytime: Bool {
        guard
            let sunrise = sunrise,
            let sunset = sunset
        else {
            return false
        }
    
        let beginningOfDay = sunrise.secondsFromMidnight() // previously sunrise.timeIntervalSince1970
        let endOfDay = sunset.secondsFromMidnight() // previously sunset.timeIntervalSince1970
        let currentTime = self.date.secondsFromMidnight() // previously self.date.timeIntervalSince1970
        
        
        let isSunriseOrLater = currentTime >= beginningOfDay
        let isBeforeSunset = currentTime < endOfDay
    
        return isSunriseOrLater && isBeforeSunset
    }

And the date extension:

extension Date {
    func secondsFromMidnight() -> Int {
        let hours = Calendar.current.component(.hour, from: self)
        let minutes = Calendar.current.component(.minute, from: self)
        let seconds = Calendar.current.component(.second, from: self)
        return hours*60*60 + minutes*60 + seconds
    }
}

[BrandonRoehl]

I had encountered this and had a fix in my fork

[hungri-yeti]

Thank you guidove, my use case matches yours and your solution helps.

[ceeK]

Hi @guidove! Thank you for the report.

Just to help me pin down this bug and implement a correct fix, would you mind creating a failing test that represents your scenario? This would help tons!

[guidove]

Sorry, do not have any experience with making tests. But it's very easy to reproduce by feeding it the lat & lon mentioned above (is Mex city coordinate) and you'll need to set your device timezone to Mexico city as well probably. Then print out calculated sunrise and sunset date&time and compare them to the official ones. (Just Google 'mexico city sunrise sunset' and it will tell you right in the search results.)

[rawmean]

This solved the problem for me. I hope that this fix is not affected by daylight savings.

        sunrise = calculate(.sunrise, for: date, and: .official)! - 3600*24
        sunset = calculate(.sunset, for: date, and: .official)! - 3600*24