I have a cloud function that is scheduled to run at 8pm PDT every day to check if a certain condition is met for each user in my firestore database. If the condition is met, the function will add a document to a collection called ff_push_notifications. My problem is with the scheduling time.

Here is the function I wrote in C# to convert a DateTime object to UTC-7 for the Firestore timestamp property. It should create a timestamp for the current day, set to the provided hour/minute/second arguments.

public static Timestamp GetTimestamp(int hour, int minute, int second)
        {
            // Step 1: Get the current date and time
            DateTime currentDateTime = DateTime.Now;

            // Step 2: Set the time to hour/minute/second
            DateTime targetTimeUtcMinus7 = new DateTime(currentDateTime.Year, currentDateTime.Month, currentDateTime.Day, hour, minute, second);

            // Step 3: Convert the time to UTC
            TimeZoneInfo timeZoneUtcMinus7 = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");
            DateTime targetTimeUtc = TimeZoneInfo.ConvertTimeToUtc(targetTimeUtcMinus7, timeZoneUtcMinus7);

            // Step 4: Create a Firestore Timestamp object
            Timestamp firestoreTimestamp = Timestamp.FromDateTime(targetTimeUtc);

            return firestoreTimestamp;
        }

When I execute this function with the arguments (20, 0, 0) locally, I get the current day at 8pm UTC-7. When this function executes server side at its scheduled time (7:00pm), the timestamp set in the document is tomorrow at 8:00pm.

So as you can see in this screenshot, the timestamp for the cloud function execution is May 27 at 7:00pm, but the scheduled time is being set to May 28th at 8:00pm instead of May 27th.

Now, since this GetTimestamp() method runs just fine locally, I suspect the issue is with the server side time being different than my local machine. How might I overcome this issue?