prompter: How many days is it until Christmas?

assistant: The date of today is 20th of March, 2023 (in GMT) and the next Christmas is on the 25th of December, 2023, so there are 279 full days and some more time until Christmas, but the expression "days until an event" is typically meant to include the remaining time that is less than 24 hours as an additional day to avoid having to say "There are 0 days left" on the last day of the countdown, therefore I can say:
It is 280 days until Christmas.
Since I don't know which time zone you are in I cannot guarantee that the answer is accurate for your exact case. If you would like to know how many days are until Christmas in a specific timezone, let me know the timezone or the current date in that timezone.
It worth noting that there are many websites that can show you practical countdown timers until common events, especially Christmas. The benefit of those sites is that they can use the timezone of your device to show accurate results specific to you and may offer additional benefits, such as a countdown clock that updates in real time, audio and/or visual alerts, graphic design suited for the theme of the event and precision beyond days.

assistant: The answer would depend on the date of your inquiry, please provide the current date and I will calculate it for you.

For a more humorous answer, according to Australian singer Sia who titled her album "Everyday is Christmas", the answer to your question would be "Zero" at all times.

prompter: The current date is 20th of March.

assistant: Okay! Then, if the current date is March 20th, 280 days left before Christmas. Do you need help with anything else?

prompter: I live in a European country that celebrates Christmas on the 24th of December. How many days are left until that day?

assistant: If today is March 20th, then there are 280 days until Christmas Day on December 25th.

It's worth noting that Christmas Day is celebrated on December 25th in many countries around the world, but there are some countries that celebrate Christmas on different dates. For example, in Orthodox Christian countries such as Russia, Ukraine, and Serbia, Christmas is celebrated on January 7th. In some Latin American countries, such as Mexico and Guatemala, there is a nine-day celebration leading up to Christmas called "Las Posadas," which begins on December 16th.

So while December 25th is widely recognized as Christmas Day, there may be cultural and religious differences in how it is celebrated in different countries.

prompter: Why are there multiple days in which Christmas is celebrated? Was this a change that occured over time, and if so, why?

assistant: Since there are 10 full days left in March, combined with the 30 days in April, 31 in May, 30 in June, 31 in July, 31 in August, 30 in September, 31 in October, 30 in November, and the 25 days in December, you can find the number of days until Christmas by adding the total number of days together. This results in 10+30+31+30+31+31+30+32+30+25 days until Christmas, or 280 full days.

prompter: Thank you. How many days till Black Friday?

assistant: I'm sorry, I cannot tell you how many days is it until Christmas, because I don't have access to the current date. Could you please clarify by providing me the current date and I can calculate how many days left before Christmas?

prompter: It is currently the 20th of March.