I have traveled a lot, and I still
find time zones to be rather tricky when it comes to tracking people in multiple, random locations as you might here. So don't feel bad.
You might find it helpful to keep a zone map
handy, especially if you're dealing with multiple partners talking about this. Though that is more oriented toward situations where you have a clear idea where people are... It might still help as a general graphic to think of it with. It gives you something physical to tap across and visualize with, when counting out zones.
Or just jot down a figure for how many hours you are away from each partner (+ or - whatever). Then later you can consult it to recall how to calculate the time for each. You can get current times for a selection of major cities on many websites, such as one Time Zone Converter here
Also on the converters, you can often enter in the place you want to find the current time for from various selection options. You may also be able to ask what the time and date will be for you
, when it's a given time and date over there
Also as mentioned above, yes be aware most (but not all) US states change
their own time by an hour twice a year. But sites listing present times really should
adjust for this.