


Zone Forecast Product
Issued by NWS Tiyan, Guam
Issued by NWS Tiyan, Guam
880 FPMY50 PGUM 180515 ZFPGUM Zone Forecast for Guam and the Northern Marianas National Weather Service Tiyan GU 315 PM ChST Mon Aug 18 2025 GUZ001-MPZ001-182000- Guam-Rota- 315 PM ChST Mon Aug 18 2025 .TONIGHT...Breezy. Mostly cloudy with scattered showers becoming cloudy with widespread locally heavy showers late evening. East winds 15 to 25 mph. Gusts to 35 mph possible near heavier showers. Lows around 75. Chance of showers 80 percent. .TUESDAY...Breezy at times. Cloudy with numerous showers becoming mostly cloudy with scattered showers around noon. Isolated thunderstorms. Locally heavy showers possible in the morning. Southeast winds 15 to 25 mph. Highs around 88. Chance of showers 60 percent. .TUESDAY NIGHT...Mostly cloudy with scattered showers and isolated thunderstorms. Southeast winds 10 to 15 mph. Lows around 79. Chance of showers 40 percent. .WEDNESDAY THROUGH THURSDAY...Partly cloudy with isolated showers and thunderstorms. Northeast winds 5 to 15 mph. Highs around 88. Lows around 79. Chance of showers 20 percent. .THURSDAY NIGHT AND FRIDAY...Mostly cloudy. A 30 percent chance of showers and a slight chance of thunderstorms. Lows in the upper 70s. Highs in the upper 80s. .FRIDAY NIGHT THROUGH SUNDAY...Mostly cloudy with a 20 percent chance of showers and thunderstorms. Lows in the upper 70s. Highs in the upper 80s. .SUNDAY NIGHT...Mostly cloudy with a 30 percent chance of showers and a slight chance of thunderstorms. Lows in the upper 70s. .MONDAY...Partly sunny with a 20 percent chance of showers and thunderstorms. Highs in the upper 80s. $$ MPZ002-003-182000- Tinian-Saipan- 315 PM ChST Mon Aug 18 2025 .TONIGHT...Breezy at times. Mostly cloudy with scattered showers becoming cloudy with numerous showers around midnight. Isolated thunderstorms. Locally heavy showers possible starting around midnight. East winds 15 to 25 mph. Gusts to 35 mph possible near heavier showers. Lows around 76. Chance of showers 60 percent. .TUESDAY AND TUESDAY NIGHT...Partly sunny with scattered showers and isolated thunderstorms. East winds 15 to 20 mph becoming southeast 10 to 15 mph in the evening. Highs around 87. Lows around 78. Chance of showers 40 percent. .WEDNESDAY THROUGH THURSDAY...Partly cloudy. Isolated showers and thunderstorms. East winds 10 to 15 mph. Highs around 88. Lows around 78. Highs around 87. Chance of showers 20 percent. .THURSDAY NIGHT THROUGH SATURDAY...Mostly cloudy with a 20 percent chance of showers and thunderstorms. Lows in the upper 70s. Highs in the upper 80s. .SATURDAY NIGHT...Mostly cloudy with a 30 percent chance of showers and a slight chance of thunderstorms. Lows in the upper 70s. .SUNDAY...Partly sunny with a 20 percent chance of showers and thunderstorms. Highs in the upper 80s. .SUNDAY NIGHT AND MONDAY...Mostly cloudy. A 30 percent chance of showers and a slight chance of thunderstorms. Lows in the upper 70s. Highs in the upper 80s. $$