Continuing the discussion from Changing timezone on account usage:
I can’t see any timezone setting in my API preferences, profile page 
, OpenAI Platform
The more important question is which is the timezone used in the replies from the API:
What is timezone used in created below, for example?
{
"id": "<<actual Id hidden>>",
"object": "chat.completion",
"created": 1699789391,
"model": "gpt-4-0613",
"choices": [
{
"index": 0,
"message": {
"role": "assistant",
"content": "<<actual response from assistant>>"
},
"finish_reason": "stop"
}
],
"usage": {
"prompt_tokens": 473,
"completion_tokens": 115,
"total_tokens": 588
}
}