yearsofweather

Guam in December:
hot, rain on every second day

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

Mean high30°Hottest day 31.6° (2022)
Mean low25°Coldest night 23.2° (2015)
Rain days19 days11-28 by year
Rainfall121mmDaylight 11.4 → 11.3 h
Guam's 12 months iBest: December to February
Trip types Beach Poorfrequent rainSightseeing on foot Poorhot, frequent rain and muggy
Humidity82%31 muggy days
Clear days8 days4 overcast days
Mean wind29 km/h15 windy days
Sea temperature29.1°28.9-29.3° by year (last 6)
Sunrise / sunset (15th)06:36 / 17:56Daylight 11.4 → 11.3 h

Guam in December

The weather settles as the dry season approaches. December 8 is the feast of Santa Marian Kamalen, Guam's patron saint, with a procession around the cathedral in Hagatna. Book flights and rooms early for the year-end holidays.

It was a hot month: 30°C by day and 25°C after dark. Rain fell on more than half the days: 19 on average. Averages hide a lot here: one year saw 11, another 28.

25 days past 30°C made it a month for early starts and a long lunch indoors.

Typhoons i

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

  • Dolphin (2008), 294 km away tropical storm
1 12 13 24 35 16 37 48 49 610 411 112

Date by date i

‹ November December 2026 January ›
Sun
Mon
Tue
Wed
Thu
Fri
Sat
Week
1-5rain on 76% of days31° 25°
6-12rain on 60% of days30° 25°
13-19rain on 57% of days30° 25°
20-26rain on 62% of days30° 25°
27-31rain on 54% of days30° 25°

0-5/206-8/209-11/2012-20/20

1-5rain on 76% of days31° 25°
6-12rain on 60% of days30° 25°
13-19rain on 57% of days30° 25°
20-26rain on 62% of days30° 25°
27-31rain on 54% of days30° 25°
Tap another date to change

20062mm
20073mm
20085mm
200910mm
20104mm
20112mm
20122mm
201313mm
2014none
2015none
20165mm
2017none
201814mm
20195mm
20204mm
202133mm
20222mm
20235mm
20242mm
202515mm
Holidays in December (2026)
  • December 8 Our Lady of Camarin Day
  • December 25 Christmas Day

1 Local public holiday or break (busier, pricier)

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
5 d 20 d
2007
3 d 18 d
2008
4 d 17 d
2009
4 d 19 d
2010
4 d 16 d
2011
7 d 23 d
2012
4 d 19 d
2013
2 d 15 d
2014
3 d 14 d
2015
5 d 15 d
2016
4 d 20 d
2017
7 d 23 d
2018
7 d 25 d
2019
2 d 11 d
2020
4 d 18 d
2021
3 d 15 d
2022
5 d 28 d
2023
6 d 27 d
2024
3 d 21 d
2025
2 d 17 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
17
16
14
13
16
10
12
13
12
10
14
13
11
14
12
8
14
11
10
15
12
14
10
12
13
11
10
14
10
8
12
Rain days on trip
53444742354772435632

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

One row per year, one cell per day. 2019 had 11 rain days, 2022 had 28.

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 December?

Over the past 20 years December averaged 19 rain days (1 mm or more) out of 31. Individual years ran from 11 in the driest to 28 in the wettest.

What should I wear in Guam in December?

Days averaged 30°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 December?

Sea surface temperature averaged 29.1°C in December, warm enough to stay in for a long swim. Year to year it ranged 28.9-29.3°C. Check local flags for waves and jellyfish on the day.

Is December a good time to visit Guam?

On warmth and rain days alone, Guam's easiest months were December to February. December ranked 3 of 12, close to the top.

Is Guam humid in December?

Mean relative humidity was 82%, with about 31 muggy days (dew point of 20°C or more) in the month.