HONOLULU (AP) — Hawaii’s regular sunshine, short rain showers and clean air come together to create some of the planet’s best conditions for viewing rainbows. They’re such a frequent sight that a University of Hawaii professor calls the state the “rainbow capital of the world.”
Right now it’s the winter rainy season in the islands, which means the odds of seeing a rainbow are even higher than usual.
Rainbows emerge so often in Hawaii they’ve become popular symbols of island life. Pictures of them adorn buildings, the sides of public buses and appear on standard vehicle license plates. University of Hawaii sports teams are even named after rainbows.
“For me, rainbows really signify hope and new beginnings,” said Liane Usher, the president of the Children’s Discovery Center in Honolulu, which features rainbows on its exterior wall and in its exploration rooms. “I can’t ever help but smile whenever I see a rainbow after the rain.”
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Here are some things to know about rainbows in Hawaii.
Where can I find rainbows?
Rainbows form when raindrops refract sunlight into a spectrum of colors. The brighter the sun, the clearer the rainbow.
Look for them when it is both sunny and raining at the same time. They will appear opposite the sun. They will seem larger and higher in the sky in the early morning and late afternoon, when the sun is lower on the horizon.
Steven Businger, professor of atmospheric sciences at the University of Hawaii at Manoa, says the archipelago’s trade winds bring many small showers with enough blue sky between them for the sun to shine through.
Hawaii’s clean air also helps. Other places tend to have more air particles from dust, pollen and cars. Conditions improve further during Hawaii’s rainy season, which lasts from October through April.
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“Hawaii has maybe the best rainbows on the planet,” Businger said.
Businger created an app called RainbowChase to help people find rainbows in Hawaii.
Rainbows are so prevalent that there are about 20 names for them in the Hawaiian language, according to a Manoa website, including distinct words for rainbow fragments and those that sit low on the horizon.
What role do rainbows play in Native Hawaiian culture?
Rainbows represent divine or supernatural power in Native Hawaiian tradition.
Sam ‘Ohu Gon III, senior scientist and cultural adviser at The Nature Conservancy in Hawaii, said rainbows are considered a symbol of Kāne, one of the four main gods in Hawaiian tradition. Traditionally, the closer one got to a rainbow, the more likely they were to encounter a supernatural force, or an extremely powerful or chiefly person, he said.
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In one centuries-old story, a rainbow appears over the secluded home of a Hawaiian princess for four straight days. Another emerges above the ocean when her suitor arrives, a man so strong his punch pierces an opponent’s chest like a spear.
To Hinaleimoana Wong-Kalu, a teacher and Native Hawaiian cultural practitioner, a rainbow signals an “aumakua,” which is a deified ancestor or a family or personal god.
“When those of our loved ones go before us, they precede us in life and they leave us in this realm. They are able sometimes to show their presence,” Wong-Kalu said. “The rainbow is one of those ways.”
Rainbows let her know spiritual protection is present and that she is loved and watched over, said Wong-Kalu, who is also known as Kumu Hina.
When did rainbows become symbols of island life?
Rainbow imagery decorates everything from buildings and restaurant facades to athletic uniforms.
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The Hawaii men’s athletic teams are called Rainbow Warriors and the women’s teams are Rainbow Wahine, using the Hawaiian word for women. The teams are called ‘Bows’ for short.
The origin of the rainbow mascot dates to New Year’s Day in 1924. Hawaii was locked in a scoreless tie against the visiting Oregon Aggies when a rainbow appeared over the field. Hawaii scored soon after and reporters began calling the team the Rainbows, according to the book “Hawai’i Sports: History, Facts and Statistics.”
The Hawaii football team in 2000 dropped “Rainbow” from its nickname when a coach expressed concern it carried a “stigma” because of its association with the LGBTQ+ community. The school restored the name in 2013.
Will climate change affect rainbows?
When Kimberly Carlson was a professor at Manoa, she saw a rainbow outside her apartment window that made her wonder how climate change would affect them.
Now a New York University environmental studies professor, she’s studied the impact over the next century.
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Her team’s analysis, published in a paper two years ago, predicts Brazil, the Mediterranean and parts of Central Africa will have fewer rainbows by 2100. They found places that currently get lots of snow, but that will instead receive more rain, will likely see more rainbows. Alaska falls in that category.
Scientists believe rainbows will continue to be plentiful in Hawaii, but in the coming decades, longer dry spells might lead to fewer rainbows on the arid, leeward sides of the islands, Businger, the atmospheric sciences professor, said. Maui and the Big Island might be particularly affected, he said.
The singular experience of glimpsing a rainbow makes them worth studying, he said.
“Rainbows are a cultural touchstone for us. They cause us to stand still and for a moment, forget about the past and the future,” Businger said. “We are really in the moment when we see a spectacular rainbow, and that’s a rare experience in our busy lives.”
The Hawaii Foodbank Kauai received two major grants of $25,000 each on Thursday: one from Kauai HMS Host and The Journey for Good Foundation by Alvota, and one from DraftKings and FanDuel.
A team from the Kauai HMS Host and The Journey for Good Foundation by Alvota visited the Puhi facility to present a check for $25,000 in support of the work being done by the Hawaii Foodbank Kauai crew.
“The opportunity to partner with The Journey for Good Foundation by Alvota was truly a gift given to us by our local HMS Host team,” Hawaii Foodbank Kauai Assistant Director Tisha Remigio said in an email. “When this amazing group came to volunteer last month, they got to see the true, on-the-ground operations of our food bank and what it really means to keep our families fed here on Kauai.”
“We learned that the funds for The Journey for Good Foundation come from such a simple, grassroots idea — those change bins at the airport checkout stands where customers can drop their loose change,” Remigio continued. “It’s incredible how that money, which seems so small, creates such a massive impact, such as the grant award. Our local HMS Host is such a wonderful group of people, and we are so fortunate for their ongoing support, not only with this monetary grant, but with the essential grocery rescue work we do with them on a weekly basis. We truly hope this inspires others to adopt a small and simple, yet everlasting, impact idea like this to help those in need on Kauai.”
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The Hawaii Foodbank Kauai also announced, in a Thursday press release, the receipt of a $25,000 donation from DraftKings and FanDuel to directly support the purchase of an additional food delivery vehicle for the Hawaii Foodbank Kauai’s mobile food pantry program.
“DraftKings is committed to strengthening communities,” said Sabrina Macias, Senior Vice President of Global Communications and CSR at DraftKings. “We’re proud to support Hawaii Foodbank Kauai in expanding access to fresh, reliable food resources, and helping families across the island receive the nourishment they need.”
The DraftKings and FanDuel grant will also sponsor the Hawaii Foodbank Kauai’s upcoming Nourish Gala that will be held on Dec. 19 at the Royal Sonesta Kauai Resort, starting at 5 p.m.
Proceeds from the gala fundraiser will help nourish families in need across the island. Tickets and sponsorship opportunities are available by visiting the website at www.kauai.hawaiifoodbank.org, or by calling 808-482-2088.
“FanDuel is honored to support Hawaii Foodbank Kauai as part of our commitment to uplifting communities,” said Keita Young, vice president of community impact at FanDuel. “Food banks are essential pillars of local resilience, and we are proud to contribute to ensuring families across Kauai have consistent access to the food and resources they need.”
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The new vehicle will expand the Hawaii Foodbank Kauai’s ability to deliver food, including fresh produce and shelf-stable goods across the island.
“We are deeply grateful for this meaningful gift from DraftKings and FanDuel,” said Hawaii Foodbank Kauai Director Wes Perreira. “With many households on Kauai facing rising food costs, partnerships like this with DraftKings and FanDuel help ensure that none of our friends, neighbors or ohana go hungry.”
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University of Hawaii at Manoa and Lawrence Berkeley National Laboratory Teamed up To Analyze Feasibility of Geothermal Cooling Technologies
By Justin Daugherty, NLR
In areas with geologically recent volcanic activity and ample underground water flow, like the Hawaiian Islands, geothermal energy technologies present options to augment the electric grid.
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Oahu’s steep terrain and highly permeable volcanic rock enable large groundwater flow, a must for successful ground heat exchangers in Hawaii, where load is cooling dominated. Shown here is Kaena Point, the western tip of Oahu’s North Shore. Photo from Christine Doughty, Lawrence Berkeley National Laboratory.
To investigate building cooling and energy efficiency options, the University of Hawaii at Manoa’s Hawaii Groundwater and Geothermal Resources Center collaborated with scientists at Lawrence Berkeley National Laboratory through the U.S. Department of Energy’s Energy Technology Innovation Partnership Project (ETIPP).
Managed by the National Laboratory of the Rockies (NLR), formerly known as NREL, ETIPP supports remote, coastal, and island communities with technical assistance and energy planning to help them build more reliable and affordable energy systems. Communities apply for up to 24 months of technical assistance, and those communities drive the scopes and focuses of their energy projects.
University of Hawaii at Manoa joined the program in 2022 with a desire to explore geothermal options, and a new report from this project details the feasibility of developing shallow ground heat exchangers (GHEs) across Oahu and at a specific site on the island for cooling.
Geothermal heat pumps take advantage of relatively constant temperatures just under the earth’s surface, using GHEs to exchange heat with the earth. Through a system of looping pipes in the shallow ground, GHEs can move heat from a warm place to a cooler place, like how a refrigerator functions.
“High-temperature geothermal, which requires deep drilling, is required to produce electricity, but low-temperature geothermal such as GHEs, which can be accessed much nearer the ground surface, can be used for building heating and cooling, greatly lessening loads on the electric grid,” said Lawrence Berkeley National Laboratory’s Christine Doughty, staff scientist.
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“I believe both types of geothermal have potential to be an asset to Hawaii,” added Nicole Lautze, founder and director of the Hawaii Groundwater and Geothermal Resources Center.
Determining Geothermal Cooling Favorability in Hawaii
In open-loop geothermal systems, wells are drilled to extract and inject groundwater, allowing the movement of thermal heat to and from the earth. These GHEs use cooler ground water from outside the system for the cooling process and expel the warmer water afterward.
In contrast, closed-loop GHE systems continually circulate a heat-transfer solution through pipes, which transfers heat to and from the ground via thermal conduction. Groundwater needs to have temperatures that are low enough to effectively cool buildings, and groundwater flow in a GHE system works to remove built-up heat.
Hawaii has far greater needs for cooling than for heating—meaning that GHEs would add heat to the subsurface and cause the systems to not function as desired. That is where groundwater comes in: It replaces heated water from the boreholes and maintains the functionality of the GHE system. Sufficient groundwater flow, then, is essential to the considerations for GHE deployment. GHE systems may not be deployed in areas with restricted watersheds or where there is subsurface production of freshwater. Therefore, closed-loop systems may be a more reasonable option in some locations.
Left: A geographic information system map of Oahu depicts different soil permeability zones (“Ksat_Class” indicates the potential speed of groundwater flow). Right: Locations of U.S. Department of Defense lands and public and private schools—potential customers for GHE—are shown.
Numerous factors help determine whether a community or business may consider GHEs. Areas with older homes may lack efficient energy systems, and some organizations, like schools or government buildings, may prioritize more adaptive heating and cooling. Cultural considerations are also very important, and a new NLR report incorporates Hawaii communities’ perspectives on geothermal.
Economic factors are another big consideration, with the expense of deploying a system versus energy savings playing into overall cost. Modeling revealed that electricity and energy transfer demand decreased, and such reductions contributed to cost savings. Longer loan terms may help ease deployment expenses for geothermal systems.
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ETIPP researchers factored the above parameters into their analysis to develop favorability maps for closed-loop and open-loop GHE systems. They used specific geographic information system layers with 11 attributes—including elevation, geology, and soil permeability—to develop an overall favorability map for GHEs on Oahu.
For the site-specific feasibility analysis at the University of Hawaii at Manoa’s Stan Sheriff Center, researchers used a hydrogeologic model to analyze groundwater flow of a closed-loop system at the site. Restrictions on water quality—mandating that groundwater must be left in its natural state—diminished the available area for GHE system deployment across the island, while many coastal areas showed high favorability. Overlays showing potential customers and restricted areas sharpened the maps.
This closed-loop favorability map shows restricted areas where GHE development is not possible. Pixels colored dark green—the top of the color spectrum table—indicate land that is more favorable to geothermal energy.
Geothermal Cooling Potential at University of Hawaii at Manoa
From the island-wide analysis, ETIPP analysis homed in and found that the Stan Sheriff Center at the University of Hawaii at Manoa, a building with a high cooling load in an area with lots of open space surrounding it, could make a good candidate for site-specific analysis of GHE technology.
Researchers used a hydrogeologic model to analyze a potential closed-loop system at the site. They modeled groundwater and heat flow, analyzed subsurface heat flow, and completed a techno-economic analysis.
Analysis without groundwater flow showed that the GHE system may operate normally in the first year, but heat buildup would increase water temperatures significantly after that, and without groundwater to sweep heat away, there would be increased chiller demand in years two through six. Modeling that incorporated groundwater flow—with similar conditions as the Stan Sheriff Center—showed that heat would be effectively swept away from the borefield, which would enable successful GHE operation for at least 10 years. Thus, including groundwater in analysis and planning—coupled with low interest loan rates and high capital investment—may provide economic benefits to the university.
The Stan Sheriff Center (white dome in the center of the image) is located at the base of the Koolau Range. Image from Google Earth.
Cold seawater may be an option for cooling-source systems, the analysis concluded, and such a system already operates at the Natural Energy Laboratory of Hawaii. The report authors encouraged further study.
As in Hawaii, ETIPP continues to help communities explore geothermal and other technologies to help meet their energy needs through in-depth, collaborative investigation of potential solutions.
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“This ETIPP project established a strong collaboration with LBNL and the foundation for what I hope is additional grant funding to explore the potential of GHEs on the UHM campus and across the state to cool buildings and reduce load on Hawaii’s grid,” Lautze said.
The U.S. Department of Energy’s Energy Technology Innovation Partnership Project (ETIPP) is a community-led technical support program for coastal, remote, and island communities to access unique solutions and increase energy reliability. By uniting federal agencies, national laboratories, regional organizations, and community stakeholders, ETIPP provides tailored technical support to help communities achieve affordable, reliable solutions to their energy system challenges. This collaborative model leverages the combined expertise and resources of its partners to deliver comprehensive, practical solutions that align with local needs. Learn more about ETIPP.
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Comet C/2025 A6, better known as Comet Lemmon, was one of the latest icy visitors to swing through our neighborhood of the solar system, leaving astronomers and casual skywatchers equally delighted. For observers in Hawaii, the glow of the Milky Way didn’t dim the streak of light made by this comet passing through.
What is it?
Comet Lemmon was discovered in January 2025 and made its closest approach to Earth in late October 2025. But by November 2025, when this image was taken, it had brightened to about the same apparent brightness as the planet Uranus, making it visible to the naked eye even from suburban skies.
Where is it?
This image was taken atop the volcanic peak Mauna Kea, on the Big Island of Hawaii.
Comet Lemmon could be seen with the naked eye as it streaked across the sky. (Image credit: International Gemini Observatory/NOIRLab/NSF/AURAImage processing: M. Rodriguez (International Gemini Observatory/NSF NOIRLab) & M. Zamani (NSF NOIRLab))
Why is it amazing?
Comets are notoriously unpredictable, so Comet Lemmon’s surprising visibility has felt like a bit of a cosmic bonus for Hawaiian stargazers. And this was a rare treat, as the comet won’t return to Earth’s skies for another 1,350 years, around the year 3375.
Framing this comet is the glow of our home galaxy, the Milky Way, which is easier to spot at higher elevations like Mauna Kea’s peak, where there is less light pollution. The image gives us a souvenir from a celestial visitor that won’t be back for more than a millennium.
Want to learn more?
You can learn more about comets and skywatching.
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