Climate averages 1991–2020
Blue Mountains weather
in September.
A mild, moderately wet month: the 8th warmest and the 4th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Blue Mountains: daytime highs average 15.0°C and nights cool to about 4.3°C. By daytime temperature it is the 8th warmest of the 12 months.
Expect about 53 mm of rain on roughly 8 days, which makes September a moderately wet month (the 4th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 11 h 51 min on an average September day.
The nearest other city in this atlas is Sydney (83 km away). In September its highs average 19.4°C, 4.4°C warmer than Blue Mountains, with 50 mm of rain.
Among the 32 cities listed in Australia, Blue Mountains ranks 27th of 32 for the warmest September highs and joint 20th of 32 for the driest September (rainfall, lowest first). The mean September high of those 32 cities is 20.0°C; Blue Mountains is 5.0°C cooler than that mean.
From September to October, average highs rise by 3.0°C to 18.0°C, and monthly rainfall rises from 53 mm to 75 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Blue Mountains climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 23.6°C12.8°C | 12.8°C | 126 | 15.5 | 14.114 h |
| February | 22.2°C12.6°C | 12.6°C | 148 | 15.4 | 13.313 h |
| March | 19.9°C10.8°C | 10.8°C | 115 | 15.1 | 12.312 h |
| April | 16.8°C7.7°C | 7.7°C | 56 | 9.1 | 11.311 h |
| May | 13.3°C4.6°C | 4.6°C | 48 | 6.6 | 10.410 h |
| June | 10.4°C2.7°C | 2.7°C | 62 | 7.7 | 10.010 h |
| July | 9.9°C1.5°C | 1.5°C | 37 | 6.3 | 10.110 h |
| August | 11.5°C1.8°C | 1.8°C | 46 | 6.7 | 10.911 h |
| September, selected | 15.0°C4.3°C | 4.3°C | 53 | 8.3 | 11.912 h |
| October | 18.0°C6.6°C | 6.6°C | 75 | 10.5 | 12.913 h |
| November | 20.1°C8.9°C | 8.9°C | 109 | 13.7 | 13.814 h |
| December | 22.1°C11.0°C | 11.0°C | 121 | 13.5 | 14.314 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Sydney in SeptemberAustralia · 83 kmHigh 19.4°C · Low 11.5°C · 50 mm rain
- Wollongong in SeptemberAustralia · 95 kmHigh 18.8°C · Low 12.3°C · 59 mm rain
- Central Coast in SeptemberAustralia · 101 kmHigh 19.8°C · Low 12.9°C · 51 mm rain
- Maitland in SeptemberAustralia · 158 kmHigh 21.6°C · Low 10.9°C · 37 mm rain
- Newcastle, Australia in SeptemberAustralia · 160 kmHigh 20.0°C · Low 12.8°C · 53 mm rain
- Canberra in SeptemberAustralia · 206 kmHigh 14.9°C · Low 4.0°C · 51 mm rain
- Tuggeranong in SeptemberAustralia · 222 kmHigh 14.9°C · Low 4.0°C · 67 mm rain
- Coffs Harbour in SeptemberAustralia · 462 kmHigh 21.5°C · Low 13.7°C · 43 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Blue Mountains) is explained once on the Blue Mountains year overview and on the Sources, method and limits page.