If you're scheduling something with someone non-local to yourself, you need not only know their time zone, but you also need also consider their latitude/longitude and what time of year it is so you account for the potential use of daylight saving time and their current sunrise/sunset times.
For example: if you schedule something at 7PM - is that daytime or nighttime? Well, if it's the first of October, and the person is in Kansas City, the answer is daytime. However, if they're in Phoenix, the answer is nighttime. And here's the kicker: the fact that Kansas City uses daylight saving time is irrelevant, as it would still be mostly light out even if you used standard time due to its higher latitude.
If you're scheduling something with someone non-local to yourself, you need not only know their time zone, but you also need also consider their latitude/longitude and what time of year it is so you account for the potential use of daylight saving time and their current sunrise/sunset times.
For example: if you schedule something at 7PM - is that daytime or nighttime? Well, if it's the first of October, and the person is in Kansas City, the answer is daytime. However, if they're in Phoenix, the answer is nighttime. And here's the kicker: the fact that Kansas City uses daylight saving time is irrelevant, as it would still be mostly light out even if you used standard time due to its higher latitude.