yearsofweather

Guam in August:
properly hot, rain almost daily

Guam · Records from 2006 to 2025. Not a forecast.

Mean high31°Hottest day 32.4° (2024)
Mean low25°Coldest night 23.3° (2008)
Rain days23 days14-29 by year
Rainfall451mmDaylight 12.7 → 12.4 h
Guam's 12 months iBest: December to February
Trip types Beach Poorfrequent rain and storm riskSightseeing on foot Poorhot, frequent rain, muggy and storm risk
Humidity83%31 muggy days
Clear days0 days24 overcast days
Mean wind17 km/h3 windy days
Sea temperature29.8°29.6-30.3° by year (last 6)
Sunrise / sunset (15th)06:08 / 18:43Daylight 12.7 → 12.4 h

Guam in August

One of the wettest months, and typhoon risk starts to rise. Check your travel insurance and flight change rules beforehand. A shopping or massage slot kept in reserve softens a rainy day.

Highs averaged 31°C and lows stayed at 25°C, so the heat hung on long after sunset. Rain came so often (23 days on average) that dry stretches were short and worth using. Averages hide a lot here: one year saw 14, another 29.

With 27 days above 30°C on average, most of the month felt like high summer. Each rainy day brought about 19 mm, closer to downpours than drizzle.

Typhoons i

4 of the last 20 years had a tropical storm pass within 300 km this month.

  • Saomai (2006), 7 km away tropical storm
  • Unnamed storm (2016), 72 km away tropical storm
  • Goni (2015), 116 km away typhoon strength
1 12 13 24 35 16 37 48 49 610 411 112

Date by date i

‹ July August 2027 September ›
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Week
1-7rain on 81% of days31° 25°
8-14rain on 77% of days30° 24°
15-21rain on 84% of days31° 24°
22-28rain on 69% of days31° 25°
29-31rain on 53% of days31° 25°

7-12/2013-15/2016/2017-20/20Rain was common on almost every date this month, so the shades compare dates within this month.

1-7rain on 81% of days31° 25°
8-14rain on 77% of days30° 24°
15-21rain on 84% of days31° 24°
22-28rain on 69% of days31° 25°
29-31rain on 53% of days31° 25°
Tap another date to change

200618mm
200730mm
2008none
200915mm
20103mm
20115mm
201212mm
201316mm
20141mm
201538mm
201614mm
20178mm
201840mm
201924mm
20206mm
202118mm
20226mm
2023none
202448mm
20258mm
Holidays in August (2027) · No public holidays this month.

Your trip dates, the past 20 years

Trip dates ~

You can also click two dates on the axis. Hover a cell to see that day's rain.
Trip rain days Month rain days
2006
6 d 23 d
2007
7 d 29 d
2008
1 d 14 d
2009
7 d 26 d
2010
2 d 20 d
2011
7 d 24 d
2012
6 d 28 d
2013
6 d 24 d
2014
4 d 23 d
2015
7 d 19 d
2016
6 d 24 d
2017
3 d 22 d
2018
7 d 24 d
2019
7 d 26 d
2020
6 d 23 d
2021
7 d 29 d
2022
6 d 21 d
2023
6 d 26 d
2024
5 d 19 d
2025
7 d 23 d
Years with rain
Tap a date to start, tap another to end. Each cell is that date in one year.
'06'07'08'09'10'11'12'13'14'15'16'17'18'19'20'21'22'23'24'25
of 20
15
18
18
14
17
16
15
14
15
17
16
13
16
17
17
16
18
17
14
18
18
13
13
17
14
13
13
13
7
9
16
Rain days on trip
67172766476377676657

No rain1-9 mm10 mm or more Dates outside your trip are dimmed.

One row per year, one cell per day. 2008 had 14 rain days, 2007 had 29.

Guam through the year

MonthHighLowRain daysRainfallSea
JanuaryGood 30°24°18 days163mm 29°
FebruaryGood 30°24°13 days100mm 28°
March 31°24°15 days91mm 28°
April 31°25°16 days104mm 29°
May 32°25°17 days139mm 29°
June 31°25°19 days155mm 30°
July 31°25°22 days314mm 30°
August 31°25°23 days451mm 30°
September 31°25°24 days444mm 30°
October 31°25°24 days427mm 30°
November 31°25°20 days186mm 30°
DecemberGood 30°25°19 days121mm 29°

Common questions

Does it rain a lot in Guam in August?

Over the past 20 years August averaged 23 rain days (1 mm or more) out of 31. Individual years ran from 14 in the driest to 29 in the wettest.

What should I wear in Guam in August?

Days averaged 31°C and nights 25°C. Pack an umbrella, sandals that can get wet, T-shirts, sunscreen plus a hat, a swimsuit, and insect repellent.

Can you swim in Guam in August?

Sea surface temperature averaged 29.8°C in August, warm enough to stay in for a long swim. Year to year it ranged 29.6-30.3°C. Check local flags for waves and jellyfish on the day.

Is August a good time to visit Guam?

On warmth and rain days alone, Guam's easiest months were December to February. August ranked 5 of 12.

Is Guam humid in August?

Mean relative humidity was 83%, with about 31 muggy days (dew point of 20°C or more) in the month.