Avg High
Sydney in December
Avg Low
Rain
Daylight
14h
What to expect
Sydney is in early summer during December, with the season well established by this point. It leans warmly comfortable through the day, and a gentle drop-off once the sun goes down. Daylight stays generous for longer outdoor plans. Conditions tend to feel steady, which makes planning simple.
December in context
How it compares to the rest of the year in Sydney.
Hottest (avg)
#3 / 12
Wettest (avg)
#8 / 12
Daylight Hours
#1 / 12
Windiest (avg)
#3 / 12
Highest UV
#1 / 12
Most Humid
#7 / 12
Monthly climate breakdown
Temperature
- Daytime high
-
- Nighttime low
-
- Feels like (avg)
-
Sunshine
- Daylight hours
- 14.4 h
- UV index (max)
- 9
- Typical sun hours
- 05:39 - 20:01
Rain & Snow
- Total rain
-
- Rainy days
- 13 days
- Cloud cover (avg)
- 55%
Humidity & Wind
- Humidity (avg)
- 72%
- Wind (avg)
-
- Wind (max gusts)
-
Daily climate explorer
Day 15 selected for December. Typical high 24.0°C and low 18.0°C.
Typical disruptions in December
Based on 30 years of historical data, these are the disruption patterns most likely to affect plans in December.
Rain High impact
Washout risk Measures: Washout day risk. Observed about 10% of days (3.1 days/month) in December. Historical risk signal only, not a day-by-day forecast.
3.1 days / month
~10% of days
Why this matters
- Expected days 3.1 days / month
- Probability ~10% of days
- Intensity Up to ~27mm (P95)
Washout conditions are possible on ~3 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Wind High impact
Strong gusts Measures: Strong gust days (>=60 km/h). Observed about 7% of days (2.3 days/month) in December. Historical risk signal only, not a day-by-day forecast.
2.3 days / month
~7% of days
Why this matters
- Expected days 2.3 days / month
- Probability ~7% of days
- Intensity Up to ~79km/h (P95)
Strong gusts are possible on ~2 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Heat High impact
Very hot feels-like Measures: Very hot feels-like days (>=35C). Observed about 5% of days (1.5 days/month) in December. Historical risk signal only, not a day-by-day forecast.
1.5 days / month
~5% of days
Why this matters
- Expected days 1.5 days / month
- Probability ~5% of days
- Intensity Up to ~41°C (P95)
Very hot feels-like conditions are possible on ~1 days. Midday activity often needs adjustment around shade, hydration, and indoor fallback options.
Heat Moderate
Hot feels-like days Measures: Hot feels-like days (>=32C). Observed about 13% of days (4.1 days/month) in December. Historical risk signal only, not a day-by-day forecast.
4.1 days / month
~13% of days
Why this matters
- Expected days 4.1 days / month
- Probability ~13% of days
- Intensity Up to ~39°C (P95)
Feels-like heat >=32C is possible on ~4 days. Midday activity often needs adjustment around shade, hydration, and indoor fallback options.
Rain Moderate
Rain disruption Measures: Likely rain disruption days. Observed about 11% of days (3.3 days/month) in December. Historical risk signal only, not a day-by-day forecast.
3.3 days / month
~11% of days
Why this matters
- Expected days 3.3 days / month
- Probability ~11% of days
- Intensity Up to ~25mm (P95)
Rain disruption risk appears on ~3 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Heat Moderate
Hot days Measures: Hot days (>=30C). Observed about 8% of days (2.6 days/month) in December. Historical risk signal only, not a day-by-day forecast.
2.6 days / month
~8% of days
Why this matters
- Expected days 2.6 days / month
- Probability ~8% of days
- Intensity Up to ~38°C (P95)
Hot days are possible on ~3 days. Midday activity often needs adjustment around shade, hydration, and indoor fallback options.
Show all disruptions (22 more)
Rain High impact
Heavy rain days Measures: Heavy rain days (>=10mm). Observed about 5% of days (1.5 days/month) in December. Historical risk signal only, not a day-by-day forecast.
1.5 days / month
~5% of days
Why this matters
- Expected days 1.5 days / month
- Probability ~5% of days
- Intensity Up to ~36mm (P95)
Heavy rain is possible on ~2 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Washout run Measures: Multi-day washout runs. Observed about 0.6 days/month in December. Historical risk signal only, not a day-by-day forecast.
0.6 days / month
Probability unavailable
Why this matters
- Expected days 0.6 days / month
- Probability —
- Intensity Up to ~24mm (P95)
Multi-day washout runs are possible on ~1 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Wind High impact
Stormy conditions Measures: Storm-impact proxy days. Observed about 1% of days (0.2 days/month) in December. Historical risk signal only, not a day-by-day forecast.
0.2 days / month
~1% of days
Why this matters
- Expected days 0.2 days / month
- Probability ~1% of days
- Intensity Up to ~70km/h (P95)
Stormy conditions are possible on ~0 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Rain High impact
Very heavy rain Measures: Very heavy rain days (>=25mm). Observed about 1% of days (0.2 days/month) in December. Historical risk signal only, not a day-by-day forecast.
0.2 days / month
~1% of days
Why this matters
- Expected days 0.2 days / month
- Probability ~1% of days
- Intensity Up to ~45mm (P95)
Very heavy rain is possible on ~0 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Humidity Moderate
Muggy days Measures: Muggy days (dew point >=20C). Observed about 4% of days (1.1 days/month) in December. Historical risk signal only, not a day-by-day forecast.
1.1 days / month
~4% of days
Why this matters
- Expected days 1.1 days / month
- Probability ~4% of days
- Intensity Up to ~21°C (P95)
Muggy conditions are possible on ~1 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Wind Minor
Gusty days Measures: Gusty days (>=40 km/h). Observed about 65% of days (20.1 days/month) in December. Historical risk signal only, not a day-by-day forecast.
20.1 days / month
~65% of days
Why this matters
- Expected days 20.1 days / month
- Probability ~65% of days
- Intensity Up to ~63km/h (P95)
Gusty conditions are possible on ~20 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Rain Minor
Wet days Measures: Wet days (>=0.1mm). Observed about 53% of days (16.3 days/month) in December. Historical risk signal only, not a day-by-day forecast.
16.3 days / month
~53% of days
Why this matters
- Expected days 16.3 days / month
- Probability ~53% of days
- Intensity Up to ~16mm (P95)
Measurable rain is possible on ~16 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Cloud Minor
Cloudy days Measures: Cloudy days (cloud cover >=60%). Observed about 48% of days (15.0 days/month) in December. Historical risk signal only, not a day-by-day forecast.
15.0 days / month
~48% of days
Why this matters
- Expected days 15.0 days / month
- Probability ~48% of days
- Intensity Up to ~99% (P95)
Cloudy skies are possible on ~15 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Rain Minor
Rainy hours Measures: Rain-hours signal (>=3h rain). Observed about 39% of days (12.1 days/month) in December. Historical risk signal only, not a day-by-day forecast.
12.1 days / month
~39% of days
Why this matters
- Expected days 12.1 days / month
- Probability ~39% of days
- Intensity Up to ~18h (P95)
Several rainy hours are possible on ~12 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Cloud Minor
Mostly cloudy days Measures: Mostly cloudy days (cloud cover >=80%). Observed about 26% of days (8.0 days/month) in December. Historical risk signal only, not a day-by-day forecast.
8.0 days / month
~26% of days
Why this matters
- Expected days 8.0 days / month
- Probability ~26% of days
- Intensity Up to ~100% (P95)
Mostly cloudy skies are possible on ~8 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Rain Minor
Wet most of day Measures: Wet-most-of-day signal (>=6h rain). Observed about 23% of days (7.0 days/month) in December. Historical risk signal only, not a day-by-day forecast.
7.0 days / month
~23% of days
Why this matters
- Expected days 7.0 days / month
- Probability ~23% of days
- Intensity Up to ~20h (P95)
Wet-most-of-day conditions are possible on ~7 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Humidity Minor
Humid days Measures: Humid days (dew point >=18C). Observed about 21% of days (6.5 days/month) in December. Historical risk signal only, not a day-by-day forecast.
6.5 days / month
~21% of days
Why this matters
- Expected days 6.5 days / month
- Probability ~21% of days
- Intensity Up to ~21°C (P95)
Humid conditions are possible on ~7 days. Comfort and pace can drop quickly, so plan shorter outdoor blocks with air-conditioned backup stops.
Humidity Minor
High humidity Measures: High humidity days (RH >=80%). Observed about 20% of days (6.3 days/month) in December. Historical risk signal only, not a day-by-day forecast.
6.3 days / month
~20% of days
Why this matters
- Expected days 6.3 days / month
- Probability ~20% of days
- Intensity Up to ~89% (P95)
High humidity is possible on ~6 days. Comfort and pace can drop quickly, so plan shorter outdoor blocks with air-conditioned backup stops.
Cloud Minor
Overcast days Measures: Overcast days (cloud cover >=95%). Observed about 9% of days (2.8 days/month) in December. Historical risk signal only, not a day-by-day forecast.
2.8 days / month
~9% of days
Why this matters
- Expected days 2.8 days / month
- Probability ~9% of days
- Intensity Up to ~100% (P95)
Overcast skies are possible on ~3 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Humidity Minor
Convective risk Measures: Convective storm risk proxy. Observed about 4% of days (1.2 days/month) in December. Historical risk signal only, not a day-by-day forecast.
1.2 days / month
~4% of days
Why this matters
- Expected days 1.2 days / month
- Probability ~4% of days
- Intensity Up to ~21°C (P95)
Convective risk signal appears on ~1 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Heat Minor
Heat stress risk Measures: High heat stress days. Observed about 3% of days (0.9 days/month) in December. Historical risk signal only, not a day-by-day forecast.
0.9 days / month
~3% of days
Why this matters
- Expected days 0.9 days / month
- Probability ~3% of days
- Intensity Up to ~39°C (P95)
Heat stress is possible on ~1 days. Midday activity often needs adjustment around shade, hydration, and indoor fallback options.
Heat Minor
Very hot days Measures: Very hot days (>=35C). Observed about 1% of days (0.4 days/month) in December. Historical risk signal only, not a day-by-day forecast.
0.4 days / month
~1% of days
Why this matters
- Expected days 0.4 days / month
- Probability ~1% of days
- Intensity Up to ~40°C (P95)
Very hot days are possible on ~0 days. Midday activity often needs adjustment around shade, hydration, and indoor fallback options.
Heat Minor
Warm nights Measures: Warm nights (min >=22C). Observed about 1% of days (0.3 days/month) in December. Historical risk signal only, not a day-by-day forecast.
0.3 days / month
~1% of days
Why this matters
- Expected days 0.3 days / month
- Probability ~1% of days
- Intensity Up to ~24°C (P95)
Warm nights are possible on ~0 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Heat Minor
Feels-like heatwave Measures: Feels-like heatwave runs (>=3 days). Observed about 0.2 days/month in December. Historical risk signal only, not a day-by-day forecast.
0.2 days / month
Probability unavailable
Why this matters
- Expected days 0.2 days / month
- Probability —
- Intensity Up to ~39°C (P95)
Feels-like heatwave runs are possible on ~0 days. Midday activity often needs adjustment around shade, hydration, and indoor fallback options.
Visibility Minor
Fog-likely signal Measures: Fog-likely visibility proxy. Observed about 1% of days (0.2 days/month) in December. Historical risk signal only, not a day-by-day forecast.
0.2 days / month
~1% of days
Why this matters
- Expected days 0.2 days / month
- Probability ~1% of days
- Intensity Up to ~93% (P95)
Fog-likely conditions are possible on ~0 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Other Minor
Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data Measures: Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data. Observed about 1% of days (0.2 days/month) in December. Historical risk signal only, not a day-by-day forecast.
0.2 days / month
~1% of days
Why this matters
- Expected days 0.2 days / month
- Probability ~1% of days
- Intensity Up to ~93 (P95)
Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data is possible on ~0 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Heat Minor
Heatwave run Measures: Heatwave runs (>=3 hot days). Observed about 0.1 days/month in December. Historical risk signal only, not a day-by-day forecast.
0.1 days / month
Probability unavailable
Why this matters
- Expected days 0.1 days / month
- Probability —
- Intensity Up to ~40°C (P95)
Heatwave runs are possible on ~0 days. Midday activity often needs adjustment around shade, hydration, and indoor fallback options.
Frequently asked questions
Is December a good time to visit Sydney?
Typical December days in Sydney reach highs of 25°C (77°F) with nights around 18°C (64°F). It usually feels warm by day and mild after dark. Overall, December sits in the middle of the Sydney climate range.
What are temperatures like in December?
Daytime temperatures in December typically peak near 25°C (77°F), while nights drop to around 18°C (64°F). Expect warm afternoons and mild evenings.
How much does it rain in December?
Rainfall in December averages 56 mm (2.2 in) across roughly 13 days. Overall it is a quite rainy time of year, so a light rain jacket and waterproof shoes are very handy.
How many hours of daylight are there in December?
You can expect about 14 hours of daylight in December. Sunrise is typically around 05:39 and sunset near 20:01. You get long days with comfortable amounts of daylight.
How strong is the sun in December?
UV levels frequently reach very high levels (around 9), so strong sun protection is essential, especially around midday.
Is it windy in December?
In December, average wind speeds are around 12 km/h (7 mph), with gusts on the windiest days reaching about 57 km/h (35 mph). On the ground, it is it can feel quite windy at times, particularly when weather systems move through.