National Weather Service Miami South Florida Rainfall Accumulation Forecast – Monday, September 21, 2026 through Thursday, September 24, 2026
MIAMI, Florida – The National Weather Service in Miami forecasts another wet day across South Florida on Monday, September 21, 2026, with scattered to numerous showers and thunderstorms especially during the afternoon and early evening.
Moist southerly flow continues to hold deep tropical moisture in place, with precipitable water values near 2.1–2.3 inches.
Rain chances stay elevated through the rest of the week as that moisture lingers over the peninsula.
Soils remain saturated after daily rounds of showers and storms. Official rainfall at Miami International Airport reached 0.95 inches on Sunday.
Additional localized heavier totals across the east coast metros in recent days keep the urban flood threat elevated if storms stall over the same neighborhoods today.
NWS Miami warned this morning that several more inches of rain this week could produce continued flooding impacts, especially in metro Miami-Dade, Broward, and Palm Beach counties.
Morning coverage should stay more isolated, with the best storm chances building this afternoon into early evening.
Mean rainfall is generally about a half inch to 1 inch in many spots, but slow storm motion and efficient downpours can still produce 2–4 inches in a short time.
Primary hazards include frequent lightning, gusty winds, and localized heavy downpours. Urban and poor-drainage flooding remains the main concern, especially in spots already hit hard this week.
The Weather Prediction Center kept the South Florida metro in a marginal risk of excessive rainfall today and Tuesday. Isolated totals of 2–4 inches remain possible if storms train over the same neighborhoods.
Rain chances (Monday, September 21, 2026):
Heat risk continues today — High temperatures will rise into the upper 80s across most of South Florida, with forecast highs near 86–88°F in Miami, Fort Lauderdale, and West Palm Beach, about 87°F in Naples, and around 89°F in Everglades City.
Peak heat index values will range from about 95°F to 102°F, with the highest readings expected near Immokalee and La Belle at 102°F; Buckhead Ridge at 100°F; West Palm Beach, Fort Lauderdale, Naples, and Everglades City at 99°F; Miami at 98°F; Homestead at 97°F; Belle Glade at 96°F; and Flamingo near 95°F. Clouds and storms should keep values from climbing higher in some inland areas that see afternoon convection.
Today (Monday): A chance of showers and thunderstorms this morning, then showers and thunderstorms likely this afternoon and early evening. Partly sunny between storms, with a high near 86–88. Heat index values as high as 95–102. Light winds becoming south around 5 mph. Chance of precipitation is about 60–70% in the east metro and 50–69% inland and along the southwest coast.
Tonight: A chance of showers and thunderstorms, mainly in the evening. Mostly cloudy and humid, with a low around 75–78. Light south winds. Chance of precipitation is 40–50%.
Tuesday: A chance of showers and thunderstorms in the morning, then showers and thunderstorms likely in the afternoon. Partly sunny between storms, with a high near 87–88. Heat index values again near 100. Light south winds 5–10 mph. Chance of precipitation is 70–80%.
Tuesday Night: Showers likely with thunderstorms, especially in the evening. Mostly cloudy, with a low around 75–78. Light south wind. Chance of precipitation is 60–70%.
Wednesday: Rain chances climb again, with showers and thunderstorms likely and daytime probabilities of 80–90%. Some storms could produce heavy rainfall. High near 87–88. Urban flooding will remain a concern if storms repeatedly train over the same neighborhoods through midweek.
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