Airport Time Zones

Program.cs

using System.Text.RegularExpressions;
using GeoTimeZone;        // Import from Nuget package "GeoTimeZone"  (https://github.com/mattjohnsonpint/GeoTimeZone)
using TimeZoneConverter;  // Import from Nuget package "TimeZoneConverter"  (https://github.com/mattjohnsonpint/TimeZoneConverter)

namespace AirportTimeZones;

internal static class Program
{
    private static void Main()
    {
        // Get the airports.csv data file from here: http://ourairports.com/data/

        using var reader = File.OpenText("airports.csv");
        var header = reader.ReadLine();
        if (header == null)
            return;

        var csvRegex = new Regex("((?<=\")[^\"]*(?=\"(,|$)+)|(?<=,|^)[^,\"]*(?=,|$))", RegexOptions.Compiled);

        var columns = csvRegex.Matches(header).Select((m, i) => new { m.Value, Index = i }).ToDictionary(x => x.Value, x => x.Index);
        var typeIndex = columns["type"];
        var latIndex = columns["latitude_deg"];
        var lonIndex = columns["longitude_deg"];
        var codeIndex = columns["iata_code"];

        var results = new Dictionary<string, string>();
        string[] badCodes = { "", "-", "---", "0" };

        while (reader.ReadLine() is { } line)
        {
            var values = csvRegex.Matches(line);

            var type = values[typeIndex].Value;
            var code = values[codeIndex].Value;

            if (badCodes.Contains(code) || type == "closed" || results.ContainsKey(code))
                continue;

            var lat = double.Parse(values[latIndex].Value);
            var lon = double.Parse(values[lonIndex].Value);
            var tz = TimeZoneLookup.GetTimeZone(lat, lon).Result;

            results.Add(code, tz);
        }

        using var writer = File.CreateText("timezones.csv");
        
        writer.WriteLine("\"iata_code\",\"iana_tz\",\"windows_tz\"");
        foreach (var item in results.OrderBy(x => x.Key))
        {
            if (!TZConvert.TryIanaToWindows(item.Value, out var windowsTimeZone)) 
                windowsTimeZone = string.Empty;
            
            writer.WriteLine("\"{0}\",\"{1}\",\"{2}\"", item.Key, item.Value, windowsTimeZone);
        }
    }
}

timezones.csv

Note that while airports don't typically move, it's still possible that the time zone may occasionally need to be updated. This can happen when a new time zone is established due to a "zone split". For example, the above list was generated in May of 2015, so it is already outdated, but only affects a few airports. I'll post an updated version soon.

Ok, the list has been updated as of today, 2016-05-05, using 2016b version of tz_world map data, and then manually updated for the new zones added in 2016d (since tz_world isn't yet updated)

Reviewing the diff, I think the ourairports data also added quite a few airports, so that's yet another way this data can change.

The good news is, all of these changes are backwards compatible. If you stay up to date regularly, you should be fine.

Updated the list again, using version 2.0 of GeoTimeZone, which uses a much more accurate map. This, and new airports added to the csv file, resulted in several corrections and additions.

Updated again for current version of GeoTimeZone. Also added Windows zones to the output via TimeZoneConverter.

Updated data again with GeoTimeZone 3.2.0 (IANA 2018d)

Updated data again with GeoTimeZone 4.0.0 (IANA 2019a)

can anyone tell me how many airports are there???

@humanyu - That's evident in the data. There are 8812 rows, the first row contains headers, so there are 8811 airport codes in this data set as of the last update. Keep in mind the airport data comes from http://ourairports.com/data/