Climate averages 1991–2020
Port Moresby weather
in September.
A hot, moderately wet month: the joint 4th warmest and the 3rd driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a hot month in Port Moresby: daytime highs average 30.1°C and nights cool to about 22.8°C. By daytime temperature it is the joint 4th warmest of the 12 months.
Expect about 45 mm of rain on roughly 8 days, which makes September a moderately wet month (the 3rd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 03 min on an average September day.
The nearest other city in this atlas is Merauke (749 km away). In September its highs average 29.3°C, 0.8°C cooler than Port Moresby, with 33 mm of rain.
From September to October, average highs rise by 0.7°C to 30.8°C, and monthly rainfall rises from 45 mm to 62 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
Port Moresby climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 30.1°C23.6°C | 23.6°C | 230 | 22.9 | 12.613 h |
| February | 29.9°C23.6°C | 23.6°C | 197 | 21.1 | 12.412 h |
| March | 29.3°C23.2°C | 23.2°C | 276 | 24.9 | 12.212 h |
| April | 29.3°C23.3°C | 23.3°C | 177 | 20.2 | 11.912 h |
| May | 29.2°C23.3°C | 23.3°C | 81 | 12.2 | 11.712 h |
| June | 28.9°C23.1°C | 23.1°C | 51 | 8.6 | 11.612 h |
| July | 28.6°C22.6°C | 22.6°C | 29 | 5.2 | 11.612 h |
| August | 29.2°C22.4°C | 22.4°C | 34 | 6.4 | 11.812 h |
| September, selected | 30.1°C22.8°C | 22.8°C | 45 | 7.8 | 12.012 h |
| October | 30.8°C23.2°C | 23.2°C | 62 | 11.0 | 12.312 h |
| November | 31.0°C23.5°C | 23.5°C | 110 | 15.5 | 12.513 h |
| December | 30.6°C23.7°C | 23.7°C | 170 | 21.2 | 12.713 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
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 Port Moresby) is explained once on the Port Moresby year overview and on the Sources, method and limits page.