Christmas lands right in the middle of summer in Adelaide. You’ll usually get warm to hot days and plenty of sunshine.
Average daytime temperatures sit around 26–28 °C (79–82 °F), and nights stay mild, hovering near 15–16 °C (59–61 °F). Locals love to gather outdoors, whether it’s a backyard barbecue or a trip to the beach.
Rain rarely interrupts December plans, so you’ll probably enjoy dry weather far more often than not. Long daylight hours and clear skies let you explore the city, visit wine regions, or just relax by the coast.
If you want to swim, the sea feels cooler than you might guess, averaging about 18–20 °C (64–68 °F). Still, with warm air and festive energy, the holiday season feels comfortable for both locals and visitors.
Overview of Adelaide’s December Climate
December in Adelaide kicks off summer with warm days, cool evenings, and lots of sunshine. Rainfall stays low, and sea breezes from the coast help keep things pleasant for outdoor activities.
Summer Weather Patterns
December signals the start of summer in South Australia. Adelaide gets some of its most settled weather now.
Daytime highs usually reach 25–27°C (77–81°F), while nights cool down to about 14–15°C (57–59°F).
You’ll see mostly dry conditions, with just 4–6 days of rain and totals near 29 mm. Sunshine dominates, averaging 294 hours for the month, so daylight sticks around for ages.
Humidity is pretty low at about 39%, making the warmth feel a lot more pleasant compared to tropical Australia. Winds average 5 m/s, which brings a refreshing breeze but rarely causes a fuss.
The Gulf St Vincent keeps coastal air mild. Water temperatures of around 22°C make swimming and beach days inviting.
Comparison to Other Months
Compared to spring, December brings hotter temps and drier days. November usually sits at 22–24°C, but December climbs into the mid-20s and brings more sunshine.
Rainfall drops compared to winter and early spring. June sees over 70 mm of rain, while December comes in at less than half that amount.
January and February get hotter than December, with highs often above 30°C. December feels like a sweet spot—warm but not scorching.
Influence of Location and Geography
Adelaide’s climate gets shaped by its spot between the Mount Lofty Ranges and Gulf St Vincent. The hills block some inland heat, while the gulf sends in cooling sea breezes.
This geography means Adelaide avoids the sticky humidity of northern Australia and the bone-dry heat of the interior. You get a Mediterranean-style climate—warm, dry days and mild evenings.
The city’s coastal setting keeps temperatures pretty steady. While inland South Australia can easily top 35°C in December, Adelaide’s closeness to the gulf keeps most days in the mid-20s.
Local influences make for reliable summer weather that suits both city adventures and coastal escapes.
Typical Christmas Temperatures in Adelaide
December in Adelaide brings warm days, mild nights, and little rainfall compared to winter. Around Christmas, you get comfortable heat during the day and evenings that rarely feel chilly.
Daytime Highs and Nighttime Lows
Late December usually sees daytime highs between 25°C and 27°C (77°F to 81°F). Sometimes, a warm spell pushes things closer to 30°C (86°F).
Nights cool off but stay mild, with lows around 15°C to 17°C (59°F to 63°F). That makes evenings perfect for dinner outside or a walk along the coast.
Extreme heat above 35°C (95°F) can happen, but it’s rare at Christmas—much more likely in January or February. Most years, you’ll find the balance just right: warm but not overbearing.
Temperature Variability During December
December weather in South Australia warms up as the month goes on. Early December highs often sit around 25°C (77°F), but by the end, they can nudge up to 28°C (82°F).
Nighttime lows shift too—early December averages around 14°C (57°F), while late December brings lows near 17°C (63°F). It’s a small change, but you’ll notice it if you’re out in the evenings.
Rainfall stays limited, with only about 15–20 mm (0.6–0.8 in) for the month. This helps keep overnight temperatures steady and the overall feel warm. Expect mostly dry skies with just a slim chance of showers around Christmas.
Historical Christmas Day Temperatures
Looking at past Christmas Days in Adelaide, the weather usually falls within the typical summer range. Most years, highs land between 24°C and 30°C (75°F to 86°F), and lows hover near 15°C (59°F).
Some years have been cooler, with highs closer to 22°C (72°F). Occasionally, a heatwave pushes the mercury well above 35°C (95°F), so you never know for sure.
If you’re planning ahead, expect a warm day with clear or partly cloudy skies. You might want sun protection for the afternoon and maybe a light jacket for the evening.
Rainfall and Precipitation Trends
December in Adelaide sits right between spring and summer, bringing drier weather compared to the wetter winter months. Rainfall is light, rainy days are few, and humidity stays moderate, making it a comfortable time for outdoor plans.
Average Rainfall in December
December is one of Adelaide’s driest months. The city usually gets about 25 mm of rainfall for the whole month, far lower than July’s typical 60 mm or more.
Rain usually comes in short bursts, not long downpours. Because of that, rain rarely disrupts your plans. Most days stay clear, with just the odd passing shower.
Compared to other Aussie cities, Adelaide’s December rainfall is pretty low. Sydney and Brisbane get several times more rain because of their humid subtropical climates. Adelaide’s Mediterranean climate means dry summers are the norm.
Rainy Days Around Christmas
Rainy days in December are scarce. You’ll see about 4 to 6 days with measurable rain for the whole month. Around Christmas, the odds of rain on any one day are low, but not impossible.
Rainfall events are usually light—under 5 mm in a day. Heavy rain is rare at this time, and if it happens, it’s usually from a passing storm.
Visitors can plan outdoor activities with confidence. Still, it’s smart to pack a light rain jacket or umbrella if you’ll be outside for a while. A quick shower can pop up, but it’s not likely to ruin your day.
Humidity Levels
December humidity in Adelaide is moderate. Daytime relative humidity sits around 45–55%, while mornings can feel a bit more humid as the air holds more moisture.
This moderate humidity makes things more comfortable than in northern cities, where summer humidity often soars above 70%. With daytime highs near 27°C, the air feels warm but not stifling.
Evenings dry out as temperatures drop, making it great for outdoor dinners or gatherings. The mix of warmth and manageable humidity is a big reason people enjoy Adelaide in late December.
Sunshine Hours and Daylight
Around Christmas, Adelaide gets long daylight hours, strong sun exposure, and a high UV index. These factors shape how much time you’ll want to spend outdoors—and how you prep for the summer sun.
Average Daily Sunshine
December brings some of the year’s longest sunshine hours to Adelaide. You can expect 9–10 hours of bright sunshine per day, making it a super sunny time.
Daylight stretches to about 14.5 hours now. That’s plenty of time for outdoor activities like the beach, hiking, or wine tours.
Compared to winter, December’s sunshine is much more reliable. Rainfall averages just 24 mm, so cloudy days rarely interrupt plans. Outdoor events have a great chance of clear skies, though the odd hot spell can sneak in.
Sunrise and Sunset Times
In late December, sunrise is early—around 5:45 am—and sunset is close to 8:30 pm. You get loads of daylight for beaches, parks, and festivals.
Mornings warm up quickly, and evening light lingers long after dinner. Outdoor dining and late walks become almost irresistible.
Daylight savings in South Australia stretches evenings out even more. If you’re planning anything that needs natural light, like photography, it’s worth remembering.
UV Index and Sun Protection
December’s UV index in Adelaide is very high, often hitting 11 or above at midday. Skin can burn in less than 15 minutes if you’re not careful.
Use broad-spectrum sunscreen (SPF 30 or higher), a wide-brimmed hat, and sunglasses with UV protection. Lightweight, long sleeves help too.
The strongest UV rays strike between 10 am and 3 pm. If you’re outside then, seek shade when you can. Even on cloudy days, UV sneaks through, so don’t skip protection.
Wind and Weather Conditions
In Adelaide during December, you’ll get warm days, mild nights, and steady breezes that really shape the outdoor vibe. Dry air, reliable sunshine, and little rain make it one of the easier months for planning anything outside.
Typical Wind Speeds
Winds in December average 4 to 5 meters per second (about 14–18 km/h). You’ll notice a pleasant breeze most days—enough to rustle branches but rarely strong enough to mess up your plans.
Adelaide’s coastal spot means sea breezes are common. These usually pick up in the afternoon, cooling things off along the shore.
If you’re into outdoor sports, the wind is great for sailing or kite flying, but not so strong that it’s a problem. On calmer days, inland spots can feel warmer since you don’t get the cooling breeze.
Notable Weather Events
December rarely brings extreme weather to Adelaide, but hot spells do happen. Sometimes, temps shoot above 35°C during short heatwaves when winds pull in hot inland air.
Rainfall stays low, with just a handful of light showers. Storms don’t happen often, though you might catch a quick thunderstorm late in the month. They’re usually brief and local.
Bushfire risk goes up on hot, windy days. If you’re heading out of the city, keep in mind South Australia enforces strict fire bans during high-risk times. It pays to stay aware of local alerts if you’re exploring rural areas.
Climate Stability in December
December usually brings some of the most stable weather you’ll find in Adelaide. Most days, you’ll see clear skies and plenty of sunshine, so the days feel long and bright. Humidity stays low, so the heat feels dry—nothing like what you’d get in the tropics.
Afternoons tend to be warm, and evenings cool off nicely. Daytime highs often hit 26–28°C, while nights drop to around 15–17°C. You can plan outdoor activities pretty confidently, since the weather doesn’t swing much.
The Mediterranean climate keeps rainfall low, with less than 30 mm on average for December. Steady breezes and predictable conditions make the weather feel reliable for locals and visitors alike.
Sea Temperatures and Coastal Conditions
When you head to Adelaide’s coast in December, you’ll find mild to warm sea temperatures and decent beach weather. The winds can change things up and shape the surf a bit. Most days support swimming, water sports, or just relaxing on the sand, but the water isn’t as warm as what you’d get up north in Australia.
Average Sea Temperature in December
The sea feels more refreshing than hot in December. Water temperatures usually hover around 19–20°C (66–68°F). You might notice mornings are cooler, with the sea at about 18°C (65°F), but it can rise to 21–22°C (69–71°F) by the afternoon.
The Southern Ocean keeps the water cooler than the air, so even if the air gets above 25°C (77°F), the sea stays a few degrees lower.
You’ll probably feel a chill when you first get in, but most swimmers say it’s comfortable after a minute or two. If you really want warmer water, stick to midday or early afternoon—those are the best times for a swim.
Swimming and Beach Activities
You can swim at most of Adelaide’s metropolitan beaches in December, though the cooler water means you might not want to stay in for ages like you would up in Queensland. Families usually wade or take short swims, and more serious swimmers sometimes wear light wetsuits to stay warm longer.
Beaches like Glenelg, Henley, and Brighton offer calm, shallow water with gentle slopes, great for casual swimming. You’ll also see surf life saving patrols during summer, which makes things feel safer.
If you’re into water sports, December works for paddleboarding, kayaking, and sailing. Since you spend more time above the water, the cooler sea doesn’t matter as much for these activities.
Coastal Wind and Surf Conditions
Winds along the coast change as the day goes on. Mornings are usually calm, with just a light breeze. By afternoon, you’ll notice stronger southwesterly sea breezes that can hit 20–30 km/h. These winds keep the summer heat in check, but they also make the water choppier.
Surf stays pretty mild around Adelaide’s main beaches. The gulf is shallow, so you don’t get big waves—just small surf that’s good for beginners. If you want bigger waves, you’ll need to drive south to the Fleurieu Peninsula, where open ocean swells are more common.
It’s usually best to swim or do calmer water activities in the morning. Save sailing or windsurfing for the breezier afternoons if that’s your thing.
Microclimates and Regional Variations
Adelaide’s climate can change a lot over short distances, thanks to the local geography. Small shifts in elevation, vegetation, or how built-up an area is can create totally different weather patterns. This matters when you’re planning what to do or pack for the season.
Weather Differences in Kent Town
Kent Town sits just east of Adelaide’s city center. Because it’s in a built-up area, you’ll often get slightly warmer nights than the open suburbs. Roads and buildings hold onto heat, so evenings don’t cool off as much, which is typical in dense city spots.
Humidity can feel higher in Kent Town during summer, since the buildings block airflow. On still days, that makes things feel a bit stuffier than in nearby suburbs.
Rainfall in Kent Town usually matches Adelaide’s central averages, with December bringing light showers—about 20–25 mm. Sometimes, heavier downpours drain more slowly in the city, so streets can stay wet longer.
Sun exposure is strong, and late December often sees a UV index of 10–11. If you’re heading outside, don’t forget shade and sun protection.
Adelaide Hills and Surrounding Areas
The Adelaide Hills climb up fast just east of the city, and that sudden rise really changes the weather you get. Temperatures usually sit 3–5°C cooler than in central Adelaide, especially when evening rolls around.
If you like milder weather for Christmas gatherings outside, the Hills make things more comfortable.
You’ll notice more rain up here too. December brings 40–50 mm on average, which is about double what the city gets.
All that extra rain keeps the landscapes greener, but you might want to keep an umbrella handy for those passing showers.
Morning fog pops up more often in valleys like Stirling or Aldgate. It can make early travel a bit tricky, though it usually lifts by mid-morning.
Winds hit harder on the exposed ridges, while spots tucked away stay much calmer.
These little differences really make the Hills feel unique compared to Kent Town or the heart of Adelaide.