BulldogLowell:
which is exactly what the APIs provide.You enter the city or postal code, or a spot on the map and you get both. Daylight Savings and time zones are Political, not geographical, after all.
The true Timezone offset from UTC is not really political. It is geographical based on longitude. Sometimes the REAL timezone line is moved around a bit by the politicians for various reasons.
Daylight savings rules are purely political decisions.
But when trying to get from UTC to a local time you start with local geographical information. So I'm assuming that they attempt to map the local geographical information to their database for a lookup. While it probably works most of the time, I'm guessing it isn't correct 100% of the time.
After all, what would be the point of using a weather API without getting to select your locality?
Its been a while but when I looked at this a few years ago, I was looking at from a standpoint of automatically determining the locality.
I wanted to get from GPS coordinates to a local time and it wasn't always possible.
Even if using the Atomic clock signals from Colorado, which can tell if when DST in the USA starts, and you have access to UTC you still have to know if the local community uses DST.
Sure, you could have a human manually pick and configure the locality, but I was looking for a solution that was GPS based and the device would automatically do it with no human intervention.
Perhaps the API capabilities are better now.
yes, they could be... but they really aren't. So, if they are changing, they are events that people know about well in advance. Let's face it, governments don't make emergency changes to their timezones!
It isn't that the DST rules are changing, it is that for a given longitude or a small geographic region it can potentially be different than the surrounding community. Say for example Las Vegas decides to do it's daylight savings timing differently then the rest of the state of Nevada, then based on the GPS location being inside the city limits of Vegas, the local time is different than just outside the city limits. Even though both locations are inside the same state.
And if trying to automate this based on GPS locations, some entity has to have all that information stored and kept up to date to be able to get from a GPS location (or even a zip code) to the current local time.
If they can handle the "messy details" about the atmosphere's pressure, temperature, ozone, humidity, pollution, windspeed, etc. outside your home, I think DST would be rather boring for these guys.
Too funny. I completely agree.
--- bill