For the northern hemisphere, summer solstice is the day when the sun in the sky is at its northernmost position. In 2016, summer solstice occurs in Honolulu, Hawaii, on Monday, June 20, 2016 at 12:34 pm.
The tropic zones are bordered by latitudes 23.44° N for the Tropic of Cancer and 23.44° S for the Tropic of Capricorn. These are places on the earth’s surface that lie directly below the sun’s path in the sky. They are indicated by the pink band in the figure.
Hawaii in the Tropic of Cancer
Hawaii is the only one of the United States that lies within the tropic zone, 16° 55′ N to about 23° N. The latitude-longitude of Honolulu is 21º 18′ N, 157º 51′ W.
For places on earth lying within the tropic zones, the sun will be at zenith (directly overhead) at local noon on one or two days in the year. Right on the Tropic of Cancer, there is only one day, the June solstice. At all other places in the Tropic of Cancer, the sun passes through the zenith on two days. In Hawaii, the popular name for these two events is called Lahaina Noon, named after Lahaina, Maui. The exact dates and times vary slightly from year to year, and definitely by latitude. At the time of Lahaina Noon, the sun casts no shadow of an object that is perfectly vertical, such as a telephone pole or a flagpole.
Path of the Sun in the Sky
From the winter solstice when the sun rises from its southernmost extreme, the sun’s path in the sky moves northward, culminating at its most northern extent on the summer solstice. Thus, Lahaina noon occurs first for the southernmost Hawaiian island and moves slowly up the archipelago. As we see from the chart below, this occurs between May 18 and May 30 for the cities of Hilo, Hawaii north to Lihue, Kauai. The sun “stands still” at the solstice on June 20, and then makes its southward way. It passes directy over Honolulu on July 15 and Hilo on July 24.
Dates for Lahaina noon, 2016
- 19.7° N Hilo May 18 12:16 pm; July 24 12:27 pm.
- 20.9° N Lahaina May 24 12:23 pm; July 18 12:33 pm.
- 21.3° N Honolulu May 26 12:28 pm; July 15 12:37 pm.
- 22.0° N Lihue May 30 12:35 pm; July 11 12:42 pm.
- 23.4° N Tropic of Cancer June 20 12:34 pm (summer solstice)
Papahānaumokuākea and Mokumanamana
The Papahānaumokuākea Marine National Monument is a U.S. National Monument encompassing 140,000 square miles of the Northwestern Hawaiian Islands.
Mokumanamana is a small island in the chain; it is located at 23°35′N 164°42′W, currently 8 miles north of the Tropic of Cancer. Mokumanamana appears in the center of this chart. Moku means island in Hawaiian, and mana means spiritual energy. We can well understand that this is an Island of Great Mana, a sacred place to ancient Hawaiian people. Although it now lies just north of the Tropic of Cancer, it was once exactly on the tropic line. At that time, Mokumanamana’s Lahaina Noon date was exactly on summer solstice day, making Mokumanamana a very special place, indeed.
Addition of 2017.04.02:
This post is about Kau ka la ia ka lolo, the traditional term for the passage kau of the sun Lā at the zenith over one’s head.
At the Windward Community College in Kaneohe, Hawaii, is a Polynesian voyaging display on permanent view. It is highly recommended for those interested in how the Polynesian people journeyed over vast distances with great navigational skill. You can view a scale model of the Hōkūleʻa voyaging canoe and an introduction to Hawaiian astronomy. We thank Professor Joseph Ciotti for preparation of the exhibit and explaining it to us. Dr. Ciotti remarked that it was the eminent Hawaiian historian, Rubellite Kawena Johnson who provided him with the proper term for this celestial event.
Above is a photo we took of the Kau ka la ia ka lolo exhibit. The text reads as follows:
‘Twice a year the noontime sun passes directly overhead. Kau ka la ia ka lolo was believed to be a time of great mana. At this moment a person’s shadow (aka) disappeared and was thought to enter his sacred head. The two dates for these solar zenith passages are marked on the map for different places on O’ahu.
Note: We have only recently found the correct Hawaiian name for this event. It is Kau ka la i ka lolo. We are grateful to Rubellite Kawena Johnson and Professor Joseph Ciotti for this valuable information.