The Time Zone Surprise: Why Arizona and Hawaii Break the Rules

They are wrong. The country spans nine time zones from the Atlantic to the Pacific, and two of its 52 top-level regions—Arizona and Hawaii—do not observe daylight saving time at all. That means a postal code lookup for a zip in Phoenix, Arizona, shows the same UTC offset all year, while a zip in Los Angeles shifts twice annually. This article explains the time zones, daylight saving rules, and the geography that creates extreme differences in sunrise and sunset across the United States.

Time Zones and Daylight Saving

The United States uses nine IANA time zones for its 50 states and territories. The contiguous states span four zones: Eastern (America/New_York, UTC-05:00 in January, UTC-04:00 in July), Central (America/Chicago, UTC-06:00 in January, UTC-05:00 in July), Mountain (America/Denver, UTC-07:00 in January, UTC-06:00 in July), and Pacific (America/Los_Angeles, UTC-08:00 in January, UTC-07:00 in July). Alaska uses America/Anchorage (UTC-09:00 in January, UTC-08:00 in July), and the remote Aleutian islands use America/Adak (UTC-10:00 in January, UTC-09:00 in July). Hawaii uses Pacific/Honolulu (UTC-10:00 all year).

Daylight saving time starts on the second Sunday of March and ends on the first Sunday of November. In 2027, clocks spring forward on March 14 at 03:00 local time, and fall back on November 7 at 02:00 local time. Arizona (America/Phoenix) and Hawaii (Pacific/Honolulu) do not change clocks. That means for half the year, Arizona shares Mountain Time with Denver but in summer it matches Pacific Daylight Time. Check the current time in the country to see the live offsets.

For the most authoritative rules, consult the IANA Time Zone Database. If you need a quick reference for any zip code, the country time page lists all zones.

Sunrise and Sunset Across the Extremes

  • Capital: Washington, D.C. (America/New_York). On the June solstice 2027, sunrise is at 05:43, sunset at 20:36—a day length of 14 hours 53 minutes. On the December solstice 2026, sunrise is at 07:23, sunset at 16:49—only 9 hours 25 minutes of daylight. The sunrise and sunset for the capital show the swing of the seasons.
  • Northernmost: Barrow, Alaska (99723, America/Nome). On the June solstice 2027, the sun stays above the horizon all day—polar day. On the December solstice 2026, the sun stays below the horizon all day—polar night. At the equinoxes, day length is typical: 12 hours 20 minutes in March 2027, 12 hours 10 minutes in September 2026.
  • Southernmost: Naalehu, Hawaii (96772, Pacific/Honolulu). The year-round day length is moderate: 13 hours 16 minutes on the June solstice 2027, 10 hours 58 minutes on the December solstice 2026. No polar extremes here.
  • Easternmost: Eastport, Maine (4631, America/New_York). The June solstice 2027 sunrise is at 04:41, sunset at 20:17—15 hours 35 minutes of daylight. The December solstice 2026 sunrise is at 07:03, sunset at 15:49—only 8 hours 45 minutes.
  • Westernmost: Adak, Alaska (99546, America/Adak). The June solstice 2027 sunrise is at 06:27, sunset at 23:09—16 hours 41 minutes. The December solstice 2026 sunrise is at 09:52, sunset at 17:37—just 7 hours 45 minutes of daylight.

For any location, use the NOAA Solar Calculator to compute precise sunrise and sunset times. The sunrise and sunset across the country page shows daily values for all zones.

Geography Behind the Time Differences

The United States covers 9,826,675 km², stretching from the Atlantic Ocean to the Pacific Ocean, and from the Arctic to the tropics. Its capital, Washington, D.C., sits at latitude 38.90, longitude -77.04. The country shares land borders with Canada to the north and Mexico to the south. The highest point is 6,190 m in Alaska.

The Earth turns 15 degrees of longitude per hour. That means the sun reaches its zenith one hour later for every 15 degrees you travel west. The westernmost postal code locality, Adak, Alaska, sits at longitude -176.63, while the easternmost, Eastport, Maine, is at -67.01—a difference of 109.62 degrees. In theory, that would create a time difference of about 7.3 hours, but because Adak uses UTC-10:00 in winter and UTC-09:00 in summer, while Eastport uses UTC-05:00 in winter and UTC-04:00 in summer, the clock difference ranges from 5 to 6 hours depending on daylight saving.

Latitude drives the extreme day lengths. Barrow, Alaska, at 71.23 north, experiences polar day and polar night because its latitude lies above the Arctic Circle. Naalehu, Hawaii, at 19.07 north, stays close to 12-hour days year-round. The capital's IANA time zone page shows the zone for Washington, D.C. The Wikipedia article about the country provides additional geographic context.

Before you call a friend in Barrow or book a flight to Honolulu, check the local time and sunrise or sunset.