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Guam Weather in September
Wet season · Typhoon riskWeather in Guam during September is typically hot in the daytime and mild to warm after sunset, based on 2016–2025 averages of 30°C (85°F) / 25°C (77°F). The 10-year average shows around 29 rainy days and about 482 mm of monthly precipitation, so rain is a major part of trip planning.
Avg high85.3°F 29.6°CAvg low76.6°F 24.8°CRainy days~28.7 daysMonthly rain482.2 mm
🧳 Packing guide
What to wear in Guam in September
For what to wear in Guam in September, light, breathable clothes work best, with sun protection for long outdoor days. A compact rain shell is useful, and the latest typhoon and transport updates matter more than long-range averages close to departure.
Travel takeaway: This can still be a rewarding time to visit, but keep outdoor plans flexible and recheck the short-range forecast before travel.
🗓️ Travel timing at a glance
Guam: 12-month travel weather
Guam is generally drier from January to May and wetter from July to November. Tropical storms and typhoons are an important late-summer and autumn consideration.
JanDry seasonFebDry seasonMarDry seasonAprDry seasonMayDry seasonJunTransition seasonJulWet seasonAugWet season · Typhoon riskSepWet season · Typhoon riskOctWet season · Typhoon riskNovWet season · Typhoon riskDecTransition season
Monthly labels summarize typical climate patterns for trip planning. Always check the latest forecast and tropical-storm alerts before departure.
🎉 Trip planning check
Guam 2026 events & busy periods
Check major events, holidays and periods that may affect crowds, transport or opening hours.
⚠️ Busy / closure period
Liberation Day events
📅 Around Jul 21
Crowds and traffic controls can affect Hagåtña and parade routes, so allow extra time when driving.
Check official source →Event dates, holiday schedules and opening hours can change. Recheck the linked official tourism or government source before departure.
Guam in September · recent 3 years
Compare the most recent complete year with the two years before it. Daily high / low temperatures are shown in °F.
CalendarNo measurable rain🌧️ Rain⛈️ Thunderstorm❄️ SnowHigh / Low · °F
⭐ September 2025 · latest complete year☔ 30 days · 361.5 mm
Sun
Mon
Tue
Wed
Thu
Fri
Sat
1
31.5°C/25.6°C
🌧️ 4.2 mm
2
31.3°C/25.1°C
🌧️ 8.5 mm
3
30.6°C/25°C
🌧️ 18.9 mm
4
30.1°C/25.2°C
🌧️ 17.1 mm
5
30.3°C/25.2°C
🌧️ 19.5 mm
6
30.9°C/25.7°C
🌧️ 10.7 mm
7
32°C/25.7°C
🌧️ 11.1 mm
8
31.1°C/24.8°C
🌧️ 8.7 mm
9
31.1°C/24.5°C
🌧️ 12.9 mm
10
31.2°C/25.3°C
🌧️ 5.4 mm
11
32.1°C/25.3°C
🌧️ 14.6 mm
12
31.9°C/25°C
🌧️ 16.4 mm
13
31°C/24.4°C
🌧️ 17.7 mm
14
30.7°C/24.8°C
🌧️ 6.2 mm
15
29.5°C/25.2°C
🌧️ 15 mm
16
29°C/25.3°C
🌧️ 16.8 mm
17
30.9°C/24.7°C
🌧️ 10.7 mm
18
30.6°C/25.3°C
🌧️ 11.4 mm
19
28.7°C/24.9°C
🌧️ 25.8 mm
20
33.2°C/24.6°C
🌧️ 10.8 mm
21
30.7°C/24.9°C
🌧️ 4.8 mm
22
32°C/24.9°C
🌧️ 20.9 mm
23
30.2°C/25.1°C
🌧️ 7.6 mm
24
32.4°C/24.6°C
🌧️ 6.4 mm
25
31.6°C/24.6°C
🌧️ 9.5 mm
26
31.2°C/24°C
🌧️ 2.3 mm
27
30.7°C/24°C
🌧️ 12.1 mm
28
30.3°C/24.9°C
🌧️ 19.6 mm
29
30.1°C/24.5°C
🌧️ 14.3 mm
30
31.3°C/25.3°C
🌧️ 1.6 mm
September 2024☔ 27 days · 573.2 mm
Sun
Mon
Tue
Wed
Thu
Fri
Sat
1
30.9°C/24.2°C
🌧️ 11.4 mm
2
31.6°C/25.5°C
🌧️ 4.7 mm
3
31.4°C/24.8°C
🌧️ 8.7 mm
4
30.3°C/26°C
🌧️ 18 mm
5
27.9°C/24°C
🌧️ 32.9 mm
6
31.4°C/24.7°C
🌧️ 8.2 mm
7
31.3°C/24.7°C
No rain
8
31.8°C/25.7°C
No rain
9
30.4°C/25.2°C
🌧️ 25 mm
10
28.4°C/24.4°C
🌧️ 30.7 mm
11
25.7°C/24.6°C
🌧️ 98.3 mm
12
28.3°C/25°C
🌧️ 19.5 mm
13
28.5°C/24.9°C
🌧️ 25.5 mm
14
26.5°C/24.4°C
🌧️ 54.7 mm
15
28.8°C/24.4°C
🌧️ 35 mm
16
25.8°C/24.1°C
🌧️ 82.7 mm
17
29.4°C/24.7°C
🌧️ 8.6 mm
18
29.5°C/24°C
🌧️ 27 mm
19
30.5°C/24°C
🌧️ 27.1 mm
20
31.1°C/25°C
🌧️ 7.3 mm
21
30.4°C/25°C
🌧️ 3.1 mm
22
31.1°C/25.8°C
🌧️ 3.5 mm
23
31.2°C/24.9°C
🌧️ 3.7 mm
24
29.9°C/24.1°C
🌧️ 7.4 mm
25
30.8°C/25.6°C
🌧️ 2.9 mm
26
29.9°C/24.5°C
🌧️ 7.4 mm
27
31°C/25.5°C
🌧️ 5.9 mm
28
31.6°C/24.6°C
🌧️ 7.7 mm
29
31.5°C/25.8°C
🌧️ 4.3 mm
30
31.7°C/26.5°C
No rain
September 2023☔ 30 days · 442.9 mm
Sun
Mon
Tue
Wed
Thu
Fri
Sat
1
27.7°C/23.3°C
🌧️ 34.7 mm
2
30.6°C/24.2°C
🌧️ 12.6 mm
3
30.5°C/24.8°C
🌧️ 6.8 mm
4
30.1°C/25.4°C
🌧️ 6.7 mm
5
31.3°C/25.8°C
🌧️ 3.2 mm
6
27.9°C/24.4°C
🌧️ 20.1 mm
7
27.9°C/23.8°C
🌧️ 16 mm
8
28.8°C/24.2°C
🌧️ 32.9 mm
9
28°C/24.4°C
🌧️ 17.8 mm
10
29.1°C/24.2°C
🌧️ 8.9 mm
11
28.5°C/24.2°C
🌧️ 16 mm
12
27.5°C/25.4°C
🌧️ 24.6 mm
13
30.4°C/24.3°C
🌧️ 8.6 mm
14
30.4°C/24.9°C
🌧️ 2.4 mm
15
31.3°C/25.3°C
🌧️ 3.4 mm
16
28.8°C/24.3°C
🌧️ 22 mm
17
30.6°C/24.4°C
🌧️ 36.3 mm
18
28.9°C/24°C
🌧️ 8.7 mm
19
30.8°C/23.9°C
🌧️ 7.9 mm
20
30.7°C/23.5°C
🌧️ 6.3 mm
21
29.3°C/23.9°C
🌧️ 20.1 mm
22
28.9°C/23.8°C
🌧️ 21.7 mm
23
30.1°C/24°C
🌧️ 1.3 mm
24
30.6°C/26°C
🌧️ 2.7 mm
25
30.7°C/25.4°C
🌧️ 1 mm
26
30.7°C/25.3°C
🌧️ 12.5 mm
27
27.2°C/24.4°C
🌧️ 37 mm
28
30°C/24.4°C
🌧️ 27.2 mm
29
30.3°C/24.3°C
🌧️ 9.2 mm
30
30.7°C/24.3°C
🌧️ 14.3 mm
Historical calendars use Open-Meteo reanalysis data. A rainy day is counted when daily precipitation is at least 1 mm. Conditions at a specific hotel, beach or station can differ.
✈️ Traveling soon?
Current Guam weather and 7-day forecast
When departure is close, the latest forecast matters more than long-term averages.
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Forecast data: MET Norway · CC BY 4.0 · cached by Travel Weather Fairy
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Guam weather in other months
Switch months to compare the seasonal pattern.