Papua New Guinea weather in September - temperature, rain and is it a good time to visit?

September is one of the best months for a holiday in Papua New Guinea.

Weather in September at a glance

Daytime temperature
30°C
Night-time temperature
24°C
Sea temperature
29°C
Daylight hours
12h02min
Chance of rain
9%
Days with thunderstorms
3%
Muggy days
100%

An overview for the country. Conditions can vary between cities and regions.

Plan your trip · September

Papua New Guinea in September: weather for a week away

Compare destinations and see how many days of a typical trip met your preferred temperature range, with less than 1 mm of daily precipitation.

Historical dataNASA POWER1981-2025
City or region
Compare with history
What weather do you prefer?

Port Moresby in September: Sightseeing

1981-2025

Daytime temperature 18-28°CDaily precipitation Less than 1 mm

Days matching your plans
2.8 / 7

Weekly average; typical number of days: 0-6

At least 5 matching days
29%

of historical weeks

All 7 days match
12%

of historical weeks

How many matching days were there in a week?

Each bar shows the share of historical weeks.

5-7 days matching your preferences

When to go? Compare the months

Average matching days per week

The highest average was in August: 4.1 matching days per week.

Papua New Guinea in September: which destinations match most often?

Comparison of 5 cities and regions using your selected conditions.

Port Moresby · 1981-2025

Hot days and warm nights in September

Does the temperature drop below 20°C during hot weather?

100%of hot days with a minimum ≥20°C
100%of weeks with at least 3 warm nights*

On 100% of hot days, the temperature stayed at or above 20°C even at its coolest. This covers 93 days with a maximum of at least 30°C.

Lowest temperature on hot days

Below 18°C0%
18°C to below 20°C0%
At least 20°C100%

* A warm night is represented by the daily minimum ≥20°C. Maximum and minimum refer to the same day; this does not isolate the night following a particular hot day.

Port Moresby · Your holiday week

How much can temperatures change during a week?

Check cooler hours as well as afternoon temperatures.

Coolest time of day23.7-25.1°CWeekly minimum: typical range
Warmest day27.8-29.8°CWeekly maximum: typical range
1.6°CTypical difference between the highest and lowest daytime maxima in a week

How often does it get cooler from one day to the next?

0%of weeks with a day-to-day drop in maximum temperature of at least 5°C

Daytime temperatures usually changed gradually, but allow for cooler hours when packing.

Ranges are the 20th-80th percentiles of whole-week minima and maxima, not forecast limits. Cooling compares consecutive daily maxima, not day and night temperatures.

Compare all destinations
18-28°C · Less than 1 mm · 1981-2025
City or regionDays matching your plansAt least 5 matching daysAll 7 days match
Port Moresby2.8 / 729%12%
Lae3.9 / 743%17%
Wewak0.2 / 7<1%0%
Mount Hagen3.5 / 735%10%
Goroka3.1 / 724%6%
Where do the figures come from?

The analysis includes 1,080 complete 7-day periods out of 1,080 possible periods in 45 years (1981-2025), for Port Moresby. Every week lies entirely within the selected month. Overlapping weeks are not independent samples. Incomplete weeks are excluded.

A matching day has a daily maximum within the selected temperature range, inclusive, and precipitation below 1 mm. Trace precipitation is possible. The typical range is the 20th-80th percentile of matching days per week. Daily percentages count each calendar day once; categories can overlap.

NASA POWER provides daily MERRA-2 grid data for each location, not city weather-station measurements or an area-wide country average. These are historical frequencies, not a forecast or a measure of forecast accuracy. This comparison does not include cloud, wind, humidity, sea temperature or changes within the day, and does not assess outdoor safety. Check the current forecast before travelling. NASA POWER Daily API.

Historical frequency, not a forecast for your travel dates.

Papua New Guinea - September vs the year - annual climate
In September, Papua New Guinea averages about 30° during the day and 24° at night. It's usually fairly dry, with only about a 9% chance of rain. The sea is around 29°C - very warm for swimming.
Historical weather 1981-2025

Weather in Papua New Guinea in September: trends from 1981 to 2025

NASA POWER

From 2016 to 2025, the average daytime high was 26°C, 2.2°C warmer than in 1981-1990. 1997 was the warmest (27.5°C), while 1990 was the coolest (22.8°C).

Differences between years

How similar is the weather in September from year to year?

In 30% of the years compared, temperature and the number of wet days were close to typical for this month.

Similar means an average daily maximum within 2°C and a wet-day count within 3 days of the 1991-2020 medians. This is historical similarity, not forecast accuracy.
30%of years with similar conditions
Typical average daytime high24.7°C–26.7°C
Typical number of wet days7–19 days

Daytime temperatures in September: year by year

Monthly average daily maximum temperature: compare individual years and the longer-term trend.

45 years of data
Coolest month22.8°C 1990
Warmest month27.5°C 1997
Latest year in the data27.3°C 2025
22°23°24°25°26°27°28°1981: 23.8°C · Average daytime maximum1982: 24.2°C · Average daytime maximum1983: 24.3°C · Average daytime maximum1984: 23.4°C · Average daytime maximum1985: 23.5°C · Average daytime maximum1986: 23.3°C · Average daytime maximum1987: 24.7°C · Average daytime maximum1988: 24.2°C · Average daytime maximum1989: 23.7°C · Average daytime maximum1990: 22.8°C · Average daytime maximum1991: 25.6°C · Average daytime maximum1992: 27.4°C · Average daytime maximum1993: 27.4°C · Average daytime maximum1994: 24.7°C · Average daytime maximum1995: 25.1°C · Average daytime maximum1996: 24.6°C · Average daytime maximum1997: 27.5°C · Average daytime maximum1998: 26.9°C · Average daytime maximum1999: 24.7°C · Average daytime maximum2000: 26.6°C · Average daytime maximum2001: 25.4°C · Average daytime maximum2002: 26.7°C · Average daytime maximum2003: 24.5°C · Average daytime maximum2004: 25.7°C · Average daytime maximum2005: 23.7°C · Average daytime maximum2006: 24.2°C · Average daytime maximum2007: 24°C · Average daytime maximum2008: 25.6°C · Average daytime maximum2009: 24.7°C · Average daytime maximum2010: 25.2°C · Average daytime maximum2011: 25°C · Average daytime maximum2012: 24.1°C · Average daytime maximum2013: 25.6°C · Average daytime maximum2014: 25.4°C · Average daytime maximum2015: 27.2°C · Average daytime maximum2016: 25.6°C · Average daytime maximum2017: 27.1°C · Average daytime maximum2018: 24.9°C · Average daytime maximum2019: 25.9°C · Average daytime maximum2020: 26.2°C · Average daytime maximum2021: 24.7°C · Average daytime maximum2022: 26.2°C · Average daytime maximum2023: 27.3°C · Average daytime maximum2024: 25°C · Average daytime maximum2025: 27.3°C · Average daytime maximum1990: 22.8°C1997: 27.5°C2025: 27.3°C19811990200020102020202522°23°24°25°26°27°28°1981: 23.8°C · Average daytime maximum1982: 24.2°C · Average daytime maximum1983: 24.3°C · Average daytime maximum1984: 23.4°C · Average daytime maximum1985: 23.5°C · Average daytime maximum1986: 23.3°C · Average daytime maximum1987: 24.7°C · Average daytime maximum1988: 24.2°C · Average daytime maximum1989: 23.7°C · Average daytime maximum1990: 22.8°C · Average daytime maximum1991: 25.6°C · Average daytime maximum1992: 27.4°C · Average daytime maximum1993: 27.4°C · Average daytime maximum1994: 24.7°C · Average daytime maximum1995: 25.1°C · Average daytime maximum1996: 24.6°C · Average daytime maximum1997: 27.5°C · Average daytime maximum1998: 26.9°C · Average daytime maximum1999: 24.7°C · Average daytime maximum2000: 26.6°C · Average daytime maximum2001: 25.4°C · Average daytime maximum2002: 26.7°C · Average daytime maximum2003: 24.5°C · Average daytime maximum2004: 25.7°C · Average daytime maximum2005: 23.7°C · Average daytime maximum2006: 24.2°C · Average daytime maximum2007: 24°C · Average daytime maximum2008: 25.6°C · Average daytime maximum2009: 24.7°C · Average daytime maximum2010: 25.2°C · Average daytime maximum2011: 25°C · Average daytime maximum2012: 24.1°C · Average daytime maximum2013: 25.6°C · Average daytime maximum2014: 25.4°C · Average daytime maximum2015: 27.2°C · Average daytime maximum2016: 25.6°C · Average daytime maximum2017: 27.1°C · Average daytime maximum2018: 24.9°C · Average daytime maximum2019: 25.9°C · Average daytime maximum2020: 26.2°C · Average daytime maximum2021: 24.7°C · Average daytime maximum2022: 26.2°C · Average daytime maximum2023: 27.3°C · Average daytime maximum2024: 25°C · Average daytime maximum2025: 27.3°C · Average daytime maximum1990: 22.8°C1997: 27.5°C2025: 27.3°C198120002025
Average for each year5-year average1991-2020 reference: 25.6°C

Blue band: the 20th-80th percentile of monthly averages in 1991-2020. The thicker line is the average of five consecutive years. Highlights describe whole months, not single-day records.

View temperatures for every year
YearAverage daytime maximum5-year average
198123.8°C-
198224.2°C-
198324.3°C-
198423.4°C-
198523.5°C23.8°C
198623.3°C23.7°C
198724.7°C23.8°C
198824.2°C23.8°C
198923.7°C23.9°C
199022.8°C23.7°C
199125.6°C24.2°C
199227.4°C24.7°C
199327.4°C25.4°C
199424.7°C25.6°C
199525.1°C26°C
199624.6°C25.8°C
199727.5°C25.9°C
199826.9°C25.8°C
199924.7°C25.8°C
200026.6°C26.1°C
200125.4°C26.2°C
200226.7°C26.1°C
200324.5°C25.6°C
200425.7°C25.8°C
200523.7°C25.2°C
200624.2°C25°C
200724°C24.4°C
200825.6°C24.6°C
200924.7°C24.4°C
201025.2°C24.7°C
201125°C24.9°C
201224.1°C24.9°C
201325.6°C24.9°C
201425.4°C25.1°C
201527.2°C25.5°C
201625.6°C25.6°C
201727.1°C26.2°C
201824.9°C26°C
201925.9°C26.1°C
202026.2°C25.9°C
202124.7°C25.8°C
202226.2°C25.6°C
202327.3°C26.1°C
202425°C25.9°C
202527.3°C26.1°C

How has September changed since the 1980s?

A comparison of 1981-1990 with 2016-2025 shows how temperatures, rainfall and the frequency of longer hot spells have changed.

In the latest decade, the average daytime high was 2.2°C warmer than in 1981-1990.

Daytime high
1981-199023.8°C2016-202526°C
change: +2.2°C
Hot days
1981-19900 days2016-20250 days
change: 0 days
Warm nights
1981-19900 days2016-20250 days
change: 0 days
Wet days
1981-199017.7 days2016-202515.7 days
change: −2 days
Years with a heatwave
1981-19900%2016-20250%
change: 0 pp

How often does September bring heat, frost and rain?

Typical number of days and monthly precipitation based on the 1991-2020 climate normal.

Warm days18 dayshigh of at least 25°C
Hot days0 dayshigh of at least 30°C
Frost nights0 dayslow below 0°C
Warm nights0 dayslow of at least 20°C
Wet days13 daysat least 1 mm
Monthly rainfall62 mmtypical total

How often does it rain in Papua New Guinea in September?

The chances use every consecutive 3-, 5- and 7-day period from 1981 to 2025. A wet day has at least 1 mm of precipitation.

A full seven days without rain occurred in 14% of historical periods. At least one wet day occurred in 86% of weeks.

3 rain-free days31%historical chance
5 rain-free days20%historical chance
7 rain-free days14%historical chance
Longest dry spell6 daystypical in the month
Longest wet spell6 daystypical in the month

Heatwaves, warm nights and cool spells in September

The percentages show years with at least one run of three consecutive days or nights meeting the stated threshold.

Heatwave0%3 days with highs of at least 30°C0 of 45 years
Run of warm nights0%3 nights with lows of at least 20°C0 of 45 years
Run of frosty nights0%3 nights with lows below 0°C0 of 45 years
Marked cool spell53%3 days with highs no greater than 24.1°C24 of 45 years · most often: Days 1-10

Highest and lowest values since 1981

Highest temperature29.9°C
Coolest night12.7°C
Wettest day44.3 mm

Start, middle or end of the month - when is the weather most stable?

We compare temperatures, dry days, heavy rain and wind. The highlighted period usually has the lowest combined risk of rain and stronger winds.

Days 1-10
25.4°CDaytime high16.9°CNight
Dry days
5 days
Heavy-rain risk
6%
Hot days
0%
Stronger wind
0%
Days 11-20most stable
25.7°CDaytime high17°CNight
Dry days
6 days
Heavy-rain risk
5%
Hot days
0%
Stronger wind
0%
Day 21 to month end
25.6°CDaytime high17.4°CNight
Dry days
6 days
Heavy-rain risk
4%
Hot days
0%
Stronger wind
0%

The most stable conditions for rain and wind usually occur during: Days 11-20.

Country values are the median of data for 5 cities covered by the site. Source: NASA POWER daily gridded data (MERRA-2), 1981-2025; 1991-2020 climate normal. These are area-based model data and can differ from official weather-station records.

Papua New Guinea weather all year - average temperatures and rain

MonthDayNightChance of rain
January 32℃24℃41%
February 31℃24℃30%
March 31℃24℃42%
April 31℃24℃25%
May 30℃25℃16%
June ★ 30℃24℃10%
July ★ 30℃24℃9%
August ★ 29℃24℃11%
September 30℃24℃9%
October ★ 30℃25℃15%
November 31℃25℃14%
December 32℃25℃17%
★ - months most often recommended for travel
Travelling soon? Check the live 14-day weather forecast for Papua New Guinea.

Papua New Guinea weather - other months

JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember