American Samoa weather in September - temperature, rain and is it a good time to visit?

Weather in September at a glance

Daytime temperature: 30°C
Night-time temperature: 24°C
Sea temperature: 28°C
Daylight hours: 12h01min
Chance of rain: 22%
Days with thunderstorms: 1%
Muggy days: 100%

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

Plan your trip · September

American Samoa 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?

Pago Pago in September: Sightseeing

1981-2025

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

Days matching your plans

2.9 / 7

Weekly average; typical number of days: 1-5

At least 5 matching days

27%

of historical weeks

All 7 days match

of historical weeks

How many matching days were there in a week?

Each bar shows the share of historical weeks.

17%

0days

18%

1day

14%

2days

12%

3days

13%

4days

5days

10%

6days

7days

5-7 days matching your preferences

When to go? Compare the months

Average matching days per week

0.3Jan 0.3Feb 0.3Mar 0.4Apr 1.1May 2Jun 3.4Jul 3.4Aug 2.9Sept 1.7Oct 0.9Nov 0.6Dec

The highest average was in July: 3.4 matching days per week.

American Samoa in September: which destinations match most often?

Comparison of 1 cities and regions using your selected conditions.

Pago Pago · 1981-2025

Hot days and warm nights in September

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

—No hot days in these records

100%of weeks with at least 3 warm nights*

None of the 1,350 days reached 30°C. There are no hot days to compare, although warm nights may still occur.

* 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.

Pago Pago · Your holiday week

How much can temperatures change during a week?

Check cooler hours as well as afternoon temperatures.

Coolest time of day25.4-26.6°CWeekly minimum: typical range

Warmest day27.2-28.1°CWeekly maximum: typical range

0.9°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 region	Days matching your plans	At least 5 matching days	All 7 days match
Pago Pago	2.9 / 7	27%	8%

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 Pago Pago. 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.

American Samoa - September vs the year - annual climate

In September, American Samoa averages about 30° during the day and 24° at night. It's usually fairly dry, with only about a 22% chance of rain. The sea is around 28°C - very warm for swimming.

Historical weather 1981-2025

Weather in American Samoa in September: trends from 1981 to 2025

NASA POWER

From 2016 to 2025, the average daytime high was 27.5°C, 1°C warmer than in 1981-1990. 2016 was the warmest (27.9°C), while 1987 was the coolest (25.6°C).

Differences between years

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

In 37% 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.

37%of years with similar conditions

Typical average daytime high26.9°C–27.7°C

Typical number of wet days13–22 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 month25.6°C 1987

Warmest month27.9°C 2016

Latest year in the data27°C 2025

Average for each year5-year average1991-2020 reference: 27.3°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

Year	Average daytime maximum	5-year average
1981	27.1°C	-
1982	26.1°C	-
1983	26.7°C	-
1984	26.6°C	-
1985	26.1°C	26.5°C
1986	26.6°C	26.4°C
1987	25.6°C	26.3°C
1988	26.7°C	26.3°C
1989	26.9°C	26.4°C
1990	27.2°C	26.6°C
1991	26.8°C	26.6°C
1992	27.6°C	27°C
1993	26.9°C	27.1°C
1994	26.6°C	27°C
1995	27.2°C	27°C
1996	26.9°C	27°C
1997	26.7°C	26.9°C
1998	26.6°C	26.8°C
1999	27.3°C	26.9°C
2000	27.2°C	26.9°C
2001	26.7°C	26.9°C
2002	27°C	27°C
2003	27.5°C	27.1°C
2004	27.6°C	27.2°C
2005	27.8°C	27.3°C
2006	27.5°C	27.5°C
2007	27.8°C	27.6°C
2008	27.2°C	27.6°C
2009	26.9°C	27.4°C
2010	27.6°C	27.4°C
2011	27.1°C	27.3°C
2012	27.7°C	27.3°C
2013	27.7°C	27.4°C
2014	27.4°C	27.5°C
2015	26.5°C	27.3°C
2016	27.9°C	27.4°C
2017	27.6°C	27.4°C
2018	27.7°C	27.4°C
2019	27.5°C	27.4°C
2020	27.8°C	27.7°C
2021	27.5°C	27.6°C
2022	27.2°C	27.5°C
2023	27.5°C	27.5°C
2024	27.5°C	27.5°C
2025	27°C	27.3°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 1°C warmer than in 1981-1990.

Daytime high

1981-199026.6°C2016-202527.5°C

change: +1°C

Hot days

1981-19900 days2016-20250 days

change: 0 days

Warm nights

1981-199030 days2016-202530 days

change: 0 days

Wet days

1981-199016.5 days2016-202515.6 days

change: −0.9 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 days30 dayshigh of at least 25°C

Hot days0 dayshigh of at least 30°C

Frost nights0 dayslow below 0°C

Warm nights30 dayslow of at least 20°C

Wet days17 daysat least 1 mm

Monthly rainfall92 mmtypical total

How often does it rain in American Samoa 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 9% of historical periods. At least one wet day occurred in 91% of weeks.

3 rain-free days25%historical chance

5 rain-free days15%historical chance

7 rain-free days9%historical chance

Longest dry spell6 daystypical in the month

Longest wet spell8 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 nights100%3 nights with lows of at least 20°C45 of 45 years · most often: Days 1-10

Run of frosty nights0%3 nights with lows below 0°C0 of 45 years

Marked cool spell51%3 days with highs no greater than 26.8°C23 of 45 years · most often: Days 1-10

Highest and lowest values since 1981

Highest temperature29°C26 September 2016

Coolest night23.7°C7 September 1987

Wettest day59 mm22 September 2003

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 1-10most stable

27.2°CDaytime high26.5°CNight

Dry days: 6 days
Heavy-rain risk: 4%
Hot days: 0%
Stronger wind: 14%

Days 11-20

27.3°CDaytime high26.7°CNight

Dry days: 4 days
Heavy-rain risk: 7%
Hot days: 0%
Stronger wind: 20%

Day 21 to month end

27.3°CDaytime high26.7°CNight

Dry days: 3 days
Heavy-rain risk: 11%
Hot days: 0%
Stronger wind: 16%

The most stable conditions for rain and wind usually occur during: Days 1-10.

Country values are the median of data for 1 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.

American Samoa weather all year - average temperatures and rain

Month	Day	Night	Chance of rain
January	27℃	19℃	15%
February	27℃	21℃	18%
March	28℃	21℃	28%
April	28℃	22℃	24%
May	28℃	23℃	34%
June	29℃	23℃	23%
July	29℃	24℃	21%
August	30℃	24℃	26%
September	30℃	24℃	22%
October	30℃	24℃	17%
November	29℃	23℃	21%
December	28℃	22℃	15%

★ - months most often recommended for travel

Travelling soon? Check the live 14-day weather forecast for American Samoa.

American Samoa weather - other months

JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember