Honolulu in December: Weather, Sea Temperature, Rain Days and the Holiday Crowds

HONOLULU · DECEMBER · 21.3° N

Honolulu does not do winter the way the mainland does. December averages a high of 81.8°F and a low of 69.2°F, and the sea off the south shore sits at 78.1°F. What the month really takes away is light: 10 hours 53 minutes of it on December 15, with the sun gone by 5:53 p.m. Your vacation days are shorter than the ones June would hand you, and the last ten days of the month arrive with every school holiday in the country attached to them.

Four weeks either side move less than most people expect. November runs 2.3°F warmer by day, January runs 2.4°F cooler by night, and the water shifts under two degrees across the three months. Demand is the variable that swings: the week of Christmas books like a different destination than the first week. For the full-year picture, the month-by-month verdict takes it from here.

On this page

• Honolulu weather in DecemberHighs of 81.8°F, 2.18 inches and 3.2 rain days
• Can you swim in December?Sea at 78.1°F, and how that figure is measured
• Crowds and prices over the Christmas weeksThe December 20 to January 3 squeeze on flights and rooms
• Things to do in Honolulu in DecemberWaikiki, Diamond Head, Hanauma Bay and Pearl Harbor
• A two-day Honolulu itineraryTwo days built around a 7:00 a.m. sunrise and a 5:53 p.m. sunset
• December vs November and JanuaryThree months of air, rain and sea in one table
• Is December a good time to visit Honolulu?Our verdict, and who should shift by four weeks

Everything below is dated to this one month. Where to sleep, how long to stay and which island comes next belong to other guides, and they are linked where they matter.

Honolulu weather in December: average highs, lows and rain days

These are NOAA NCEI monthly normals for 1991 to 2020, taken at station USW00022521, the thermometer and rain gauge at Honolulu International Airport. One caveat matters more here than in most cities: that gauge sits on the leeward south shore of Oahu, a few miles from Waikiki. The windward coast and the mountains behind it take several times the rain, and this instrument never sees a drop of it. Every figure here describes the dry side of the island, which happens to be the side most visitors sleep on.

2.18 inches reads like a wet month until you count the days it falls on. An average December records at least 0.10 inch on 3.2 days, measurable rain roughly one day in ten. Most of it arrives as showers that cross, soak you and move off, rather than as a front parked over the city for three days. Plan the week as though two mornings will get wet, and treat a dry run of seven days as a gift rather than the baseline.

Between the 81.8°F afternoon and the 69.2°F hour before dawn there are 12.6 degrees, a narrow spread by mainland standards and still enough to register after dark. A 7 p.m. table outdoors in late December, with trade winds crossing it, is a light-layer evening. One long-sleeve layer, one thin rain shell and sunscreen cover the month. A 69-degree night says nothing about the sun at 11 a.m., and the sweater you packed will stay folded in the suitcase all week.

December 15 gives Honolulu 10 hours 53 minutes of daylight, sunrise at 7:00 a.m. and sunset at 5:53 p.m. local time, per sunrise-sunset.org. Hawaii keeps one clock all year, so nothing is borrowed back until spring. That puts a hard edge on the afternoon. A hike started at 4 p.m. ends in the dark, and the hour worth protecting is the one before 8 a.m., when the sand off Waikiki is quiet and the light is already up.

Can you swim in Honolulu in December? Sea temperature and what it feels like

The Open-Meteo marine model puts the sea surface off Honolulu at 78.1°F in December, averaged over 2015 to 2024. Read the small print on that number: it is the mean of daily maxima, the warmest reading of each day, so it runs a shade above a true 24-hour average. Tables that publish a full-day mean will show a degree or so less for the same water in the same month. Both are describing the same ocean, measured with different arithmetic.

For most American swimmers, 78-degree water is simply water: no gasp in the first thirty seconds, no negotiation at the shoreline. The place you notice the temperature is the second hour of snorkeling, when thin adults and children start to cool down, and a rash guard or a shorty buys that hour back. Air at 81.8°F means you dry fast when you climb out, which is exactly what January starts to withdraw at 80.5°F.

Our verified set for this month covers air, rain, daylight and sea-surface temperature. It carries no wave-height or wind series, so no figure for surf or trade-wind strength appears here. December is winter in the North Pacific, and on Oahu that plays out shore by shore rather than island-wide. Check the National Weather Service surf zone forecast and the lifeguard flags on the morning you swim, and take the sheltered south-shore beaches as the calm-water default.

How busy is Honolulu in December? Crowds, prices and the demand peak

Two calendars run through this one month. Until roughly December 20, Honolulu is an ordinary warm week with mainland schools still in session. From the week before Christmas through the first days of January, every school holiday in the country points at the same beaches at the same time. We hold no monthly hotel-rate or occupancy series for Oahu, so no ranking of cheap and expensive months appears here; the calendar fact stands on its own and is enough to plan around.

That split is really two different bookings. Flights and rooms for December 1 to 19 behave like a normal shoulder week and tolerate a decision made about a month out (est.). The holiday window, December 20 to January 3, is the one to lock early: treat Thanksgiving as the last comfortable deadline (est.), and take refundable rates while your dates can still move. A cancelable room costs nothing until the night you actually keep it.

Room quotes in Hawaii arrive with accommodation taxes added at the end, and on a seven-night stay they are not a rounding error. We could not verify a current rate in time for publication, so no percentage goes in this paragraph. Read the tax line and any resort fee on the quote before you compare two Waikiki hotels. The nightly headline and the total your card gets charged can sit a long way apart, and the gap widens with the length of the stay.

If you spend extra on one thing this month, make it the rental car, for a reason the normals themselves give you. The 2.18 inches in the table above are a leeward-shore measurement, and the windward coast and the Koolau slopes take several times that. With a car, a gray morning in Waikiki turns into a drive to the dry side, or the reverse on a windward day. Without one, the shower crossing your beach is the entire forecast for your weekend.

Things to do in Honolulu in December

December settles the swimming argument by itself: 81.8°F air over 78.1°F water, in the weeks when most of the country is scraping windshields. It is also the month with the least daylight to spend it in, 10 hours 53 minutes on the 15th, and that pushes the good hours forward. Put the hike, the snorkel and the long drive before noon, and leave the afternoon for whatever survives a passing shower.

The shortlist is walkable or a short drive away. Waikiki and Kuhio beaches for protected swimming, Ala Moana Beach Park for the calmer local stretch of the same shore, Diamond Head State Monument for the crater rim, Hanauma Bay Nature Preserve for snorkeling, Manoa Falls for the green hour behind the city, and the Pearl Harbor memorials for a half day. Diamond Head and Hanauma Bay both run entry reservations for nonresidents. We have not verified current fees or opening hours, so book on the official state and city sites.

December barely touches the water at those places and does move the air. Off the south shore the sea runs 79.0°F in November, 78.1°F in December and 77.3°F in January (marine model, 2015 to 2024), under two degrees across a quarter of the year. The air falls faster, from 84.1°F in November to 81.8°F here. That gap shows up on the Diamond Head rim and the Manoa trail, where a 10 a.m. climb is cooler work than the same climb four weeks earlier.

Free, in a city where little else is: the beaches. Waikiki, Kuhio and Ala Moana cost nothing to walk onto, and neither does the sunset, which in December lands at a civilized 5:53 p.m. instead of well after most families have eaten. Sunrise at 7:00 a.m. is the other free hour of the day, and the quieter of the two on the sand. Parking near either beach is the line item to check, not the beach itself.

Honolulu in December: a two-day itinerary

Day one stays on the south shore. Up for the 7:00 a.m. sunrise, into the water off Kuhio Beach while it is still quiet, breakfast afterward. Diamond Head between 8 and 10 with the reservation made the night before, so the crater rim is behind you before the day climbs toward its 81.8°F average. Snorkel or swim late morning, take a long lunch, and spend the early afternoon indoors when the shower risk peaks. Back on the sand by 4:30 for the last hour of light.

Day two goes east with the car: Hanauma Bay early, since reservation slots go fast, then the windward coast, and home before 5:53 p.m. so the last stretch is driven in daylight. If the sky turns, flip the order. The Pearl Harbor museums, the Bishop Museum and the Honolulu Museum of Art all absorb a wet morning, and with 3.2 measurable-rain days in an average December the odds of losing both mornings stay low. A shower over Waikiki often leaves the leeward side dry twenty minutes later.

Honolulu in December vs November and January

Across the three months the air moves more than the water. November is warmest by day at 84.1°F, with December 2.3 degrees below it. January owns the cool end of the nights at 66.8°F, 2.4 degrees under December. Rainfall totals fall steadily, 2.25 inches to 2.18 to 1.84, while the number of days carrying it climbs, 2.9 to 3.2 to 3.3. January spreads less rain over more days. (Air and rain from NOAA 1991–2020 normals, sea from the marine model, 2015–2024.)

Move four weeks back to November and you gain 2.3°F of daytime warmth, nearly a degree of sea at 79.0°F, half a rain day fewer, and a month with no holiday squeeze on flights. You give up the holiday atmosphere, if that is the reason for the trip. Move forward instead and January buys you the quiet weeks after the 3rd and the driest total of the three at 1.84 inches, paid for with 66.8°F nights and a 77.3°F ocean.

Is December a good time to visit Honolulu?

Yes for anyone whose main goal is warm water and warm air in the middle of a mainland winter: 81.8°F days and a 78.1°F ocean deliver that with no asterisk. No for travelers whose dates are locked to the last ten days of the month and whose budget has no room to move, because that window competes with the entire country’s school holiday. And no for anyone who wants long evenings, since the light goes at 5:53 p.m. and stays that way through the month.

If that lands badly, November is the better swap: 84.1°F by day, 79.0°F water, 2.9 rain days, and flights chosen without a holiday calendar on top of them. Mid-January is the other answer, quieter after the 3rd and drier at 1.84 inches, in exchange for the coolest nights of the three months. Choosing a month rather than a place? Start at our month-by-month index instead.

Of the three months, December is the only one that puts holiday-week Waikiki and water still above 78°F in the same fortnight.

The last word

Book the flight into the first half of the month unless the holiday dates are non-negotiable, and reserve Diamond Head and Hanauma Bay the moment their windows open. One figure from the normals has been held back, and it is the one that decides whether rain can wreck anything: an average December records an inch or more on just 0.5 day, so roughly one December in two sees a true soaking, and the other one never does. Carry the thin shell and leave the rest of the plan alone.

Sources & data for this guide

• December normals: high 81.8°F, low 69.2°F, 2.18 in · NOAA NCEI monthly normals 1991–2020, station USW00022521, Honolulu International Airport · checked Sep 15, 2026
• Rain days: 3.2 days at 0.10 in or more, 0.5 day at 1.00 in or more · same NOAA NCEI normals · checked Sep 15, 2026
• Sea surface 78.1°F, mean of daily maxima 2015–2024 · Open-Meteo Marine API · checked Sep 15, 2026
• November and January columns (air and rain) · NOAA NCEI 1991–2020 normals, same station; sea figures from the Open-Meteo Marine API, 2015–2024 · checked Sep 15, 2026
• Daylight 10h 53m on Dec 15, sunrise 7:00 a.m., sunset 5:53 p.m. local · sunrise-sunset.org · checked Sep 15, 2026
• We hold no hotel-rate, occupancy, wave-height or accommodation-tax figures for Oahu, so none appear above; booking lead times marked (est.) are editorial. Fees, reservation systems and hours at Diamond Head, Hanauma Bay and Pearl Harbor change · check the official sites when you book.