How do I convert UTC to PST or PDT depending upon what the current time is in California?

.net, c#, timezone

Solution

Two options:

1) Use `TimeZoneInfo` and `DateTime`:

using System;

class Test
{
    static void Main()
    {
        // Don't be fooled - this really is the Pacific time zone,
        // not just standard time...
        var zone = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");
        var utcNow = DateTime.UtcNow;
        var pacificNow = TimeZoneInfo.ConvertTimeFromUtc(utcNow, zone);

        Console.WriteLine(pacificNow);
    }
}

2) Use my Noda Time project :)

using System;
using NodaTime;

class Test
{
    static void Main()
    {
        // TZDB ID for Pacific time
        DateTimeZone zone = DateTimeZoneProviders.Tzdb["America/Los_Angeles"];
        // SystemClock implements IClock; you'd normally inject it
        // for testability
        Instant now = SystemClock.Instance.Now;

        ZonedDateTime pacificNow = now.InZone(zone);        
        Console.WriteLine(pacificNow);
    }
}

Obviously I'm biased, but I prefer to use Noda Time, primarily for three reasons:

- You can use the TZDB time zone information, which is more portable outside Windows. (You can use BCL-based zones too.)

- There are different types for various different kinds of information, which avoids the oddities of `DateTime` trying to represent three different kinds of value, and having no concept of just representing "a date" or "a time of day"

- It's designed with testability in mind

Problem

Original source