850
FPMY50 PGUM 210549
ZFPGUM

Zone Forecast for Guam and the Northern Marianas
National Weather Service Tiyan GU
349 PM ChST Mon Sep 21 2026

GUZ001-212030-
Guam-
349 PM ChST Mon Sep 21 2026

...FLOOD WATCH IN EFFECT FROM TUESDAY MORNING THROUGH WEDNESDAY
EVENING...
...HEAVY RAINFALL POSSIBLE TUESDAY THROUGH WEDNESDAY AS INVEST
91W PASSES TO THE WEST...

.TONIGHT...Mostly cloudy with scattered showers and isolated
thunderstorms. Southeast winds 10 to 15 mph. Lows around 77. Chance
of showers 40 percent.
.TUESDAY...Cloudy with numerous locally heavy showers and isolated
thunderstorms. Southeast winds 15 to 20 mph. Highs around 85. Chance
of showers 70 percent.
.TUESDAY NIGHT...Mostly cloudy with numerous locally heavy showers
and isolated thunderstorms. South winds 10 to 15 mph. Lows around 76.
Chance of showers 60 percent.
.WEDNESDAY AND WEDNESDAY NIGHT...Mostly cloudy with scattered
showers and isolated thunderstorms. Locally heavy showers possible.
Southwest winds 10 to 15 mph. Highs around 86. Lows around 77. Chance
of showers 50 percent.
.THURSDAY...Partly sunny. Scattered showers and isolated
thunderstorms in the morning, then a 40 percent chance of showers
and a slight chance of thunderstorms in the afternoon. Southwest
winds 10 to 15 mph. Highs around 87.
.THURSDAY NIGHT THROUGH MONDAY...Mostly cloudy with a chance of
showers and a slight chance of thunderstorms. Lows in the upper 70s.
Highs in the upper 80s. Chance of showers 30 percent.

$$

MPZ001>003-212030-
Rota-Tinian-Saipan-
349 PM ChST Mon Sep 21 2026

.TONIGHT...Mostly cloudy. Isolated showers and thunderstorms in the
evening, then scattered showers and isolated thunderstorms after
midnight. Southeast winds 10 to 15 mph. Lows around 77. Chance of
showers 40 percent.
.TUESDAY...Mostly cloudy with scattered showers and isolated
thunderstorms. Southeast winds 10 to 15 mph. Highs around 86. Chance
of showers 50 percent.
.TUESDAY NIGHT...Mostly cloudy with scattered showers and isolated
thunderstorms. Southeast winds 10 to 15 mph. Lows around 76. Chance
of showers 50 percent.
.WEDNESDAY AND WEDNESDAY NIGHT...Mostly cloudy with scattered
showers and isolated thunderstorms. Southwest winds 10 to 15 mph.
Highs around 86. Lows around 76. Chance of showers 50 percent.
.THURSDAY...Partly sunny. Scattered showers and isolated
thunderstorms in the morning, then a 40 percent chance of showers
and a slight chance of thunderstorms in the afternoon. Light and
variable winds. Highs around 87.
.THURSDAY NIGHT...Mostly cloudy with a 30 percent chance of showers.
Lows in the upper 70s.
.FRIDAY AND FRIDAY NIGHT...Mostly cloudy. A 30 percent chance of
showers and a slight chance of thunderstorms. Highs in the upper
80s. Lows in the upper 70s.
.SATURDAY THROUGH SUNDAY...Mostly cloudy with a 30 percent chance of
showers. Highs in the upper 80s. Lows in the upper 70s.
.SUNDAY NIGHT AND MONDAY...Mostly cloudy with a 30 percent chance of
showers and a slight chance of thunderstorms. Lows in the upper 70s.
Highs in the upper 80s.

$$