Early summer · Weather & things to do
Blue Mountains in December
Blue Mountains warms up: highs climb to 76°F (25°C), from 72°F in November, with lows of 52°F (11°C) and about 3.1 in (78 mm) of rain.
It scores 84/100 for comfort, 7th of 12, which makes it a solid shoulder-season month.
- Avg high
- 76°F (25°C)
- Avg low
- 52°F (11°C)
- Rain
- 3.1 in (78 mm)
- Humidity
- 61%
- Cloud cover
- 64%
- Daylight
- ~14 h 14 min
- Comfort score
- 84/100 · Great
What December feels like
Highs settle around 76°F (25°C), warm enough for short sleeves most of the day.
There's a big swing between day and night, about 14°C (24°F), so mornings and evenings feel much cooler than the afternoon.
Showers are part of the month, adding up to about 3.1 in (78 mm).
Plan around December
December is shoulder season: good weather, a step below the best months (January, March & April and September – November).
- Longest days of the year, about 14 h 14 min of daylight.
- Comfort holds steady from November (84 → 84/100).
- Our Sydney, Blue Mountains & the Reef route recommends May – Oct, so December falls outside its suggested window.
What to pack for December
- Light, breathable clothes76°F afternoons
- Sunscreen, sunglasses and a hathigh UV on clear days
- A warm layer for eveningsnights drop to 52°F
- Packable rain jacket or umbrellaa shower or two is likely
- Comfortable walking shoesmost places below are best reached on foot or with short walks
What to do in Blue Mountains in December
December is good outdoor weather here, so these picks lean toward the open air.
Grand Canyon Track
6 km loop near Blackheath descending into a fern-lined slot canyon.
Why now December scores 84/100 for comfort, good conditions for being outside.
Three Sisters
Three sandstone pillars above the Jamison Valley, seen from Echo Point Lookout.
Why now Highs near 76°F and 3.1 in of monthly rain make this an easy outdoor pick.
Zig Zag Railway
Heritage steam and diesel trains running down the 1860s zig-zag line from Clarence near Lithgow, with sandstone cuttings and viaducts.
Why now One to do outside while the weather is on your side.
Leura Gourmet
Cafe and deli on Leura Mall with a back dining room that looks out over the Jamison Valley.
Scenic World
Steep railway, cable car and skyway over the Jamison Valley, with rainforest boardwalks.
Nearby in December
- Sydney in December~53 mi · highs 75°F, 2.8 in rain · similar daytime temperatures, about as wet
NASA POWER 2001–2025 monthly averages on a ~50 km grid, temperatures adjusted from the grid cell's ~875 m to Blue Mountains's ~1,022 m elevation (standard lapse rate). Comfort scores weigh temperature, rain, humidity and cloud: see how we score each month. Check a forecast before you go.
Blue Mountains in December: quick answers
Is December a good time to visit Blue Mountains?
It's a good shoulder-season choice, scoring 84/100 against a best of 90 in January, March & April and September – November. Expect highs of 76°F (25°C) and 3.1 in (78 mm) of rain. Our Sydney, Blue Mountains & the Reef route recommends May – Oct, so December is outside its suggested window.
How hot is Blue Mountains in December?
Average highs are 76°F (25°C) and average lows 52°F (11°C), making it the 3rd-warmest month by daytime highs.
Does it rain a lot in Blue Mountains in December?
Some: about 3.1 in (78 mm) of rain falls across December on average, the 5th-wettest month of the year. The annual total is about 29.5 in (749 mm).
What should I pack for Blue Mountains in December?
Bring light, breathable clothes (76°F afternoons), sunscreen, sunglasses and a hat (high UV on clear days), a warm layer for evenings (nights drop to 52°F), packable rain jacket or umbrella (a shower or two is likely) and comfortable walking shoes (most places below are best reached on foot or with short walks).
More on Blue Mountains
Planning Blue Mountains in December?
Bring the crew into one shared trip: vote on dates, build the day-by-day plan, split costs and share one packing list.