Boston flood forecast
Clear today
Next flood window Mon 11:15 AM–12:00 PM
Now
Today 1:36 AM
Tide
2.5 ft
In short
In Boston, roads start to flood when the tide at NOAA's Boston station passes about 11.3 ft (MLLW). Next flood: Mon, Oct 26, 11:15 AM–12:00 PM EDT (minor flooding possible), with 3 streets forecast to flood at the peak: Chelsea St, William T. Morrissey Blvd and Marginal St.
Next 7 days
Flood windows
Mon
Oct 26
11:15 AM–12:00 PMPossibleKing tidePeak 11.4 ft · Chelsea St, William T. Morrissey Blvd, Marginal St
Tue
Oct 27
11:40 AM–1:25 PMPossibleKing tidePeak 11.7 ft · Chelsea St, William T. Morrissey Blvd, Marginal St
Wed
Oct 28
12:20–2:20 PMPossibleKing tidePeak 11.8 ft · Chelsea St, William T. Morrissey Blvd, Marginal St
Tap a day for the street-by-street forecast and a share card. Times are America/New York time.
Since 1996
Boston flood history
Days with roads at risk
1,205
since 1996
Record high water
15.16 ft
Jan 4, 2018
Days a year, then vs now
27 → 48
1996–05 vs 2016–25
Estimates only. Never drive through flood water — six inches can float a car. Follow local authorities.
How this forecast works
FloodRoute combines NOAA tide predictions for the Boston station with the elevation of every road segment in Boston. When the predicted water level rises above a road's lowest point, it's marked — amber for possible, orange for likely, red for severe. The NOAA Boston gauge shows how far the water is actually running above or below the tide tables; that difference is carried into the forecast and fades over the following days. Recent rain raises the next 24 hours. After each high tide, streets stay marked a little longer, because water drains off the road more slowly than the tide falls.
Tide source: NOAA station 8443970 (Boston). Updated 1:41 AM.
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FAQ
Boston flooding: questions, answered
Which roads flood in Boston?
The worst flood forecast in the next 30 days is Wed, Oct 28, 12:20–2:20 PM EDT (minor flooding possible). At its peak, 3 streets are forecast to flood: Chelsea St, William T. Morrissey Blvd and Marginal St. The live map shows every street, hour by hour.
When is the next flood in Boston?
Mon, Oct 26, 11:15 AM–12:00 PM EDT: minor flooding possible, peaking around 11:36 AM. FloodRoute forecasts 4 more flood windows in the next 30 days. See the street-by-street forecast for that day.
How high does the tide have to be to flood roads in Boston?
Roads start to flood when the tide at NOAA's Boston station passes about 11.3 ft (MLLW). Higher tides flood more streets, for longer. FloodRoute marks flooding as possible when the water is less than 0.5 ft above a road's low point, likely up to 1.5 ft, and severe at 1.5 ft or more.
When is the next king tide in Boston?
Sun, Oct 25 at 10:56 AM EDT: a 10.8 ft high tide predicted at NOAA's Boston station. FloodRoute calls a high tide a king tide when it is more than 0.7 ft above the station's mean higher high water (MHHW).
How can I get flood alerts for Boston?
The free FloodRoute iPhone app gives you a heads-up before flood windows in your home town; FloodRoute Pro adds street-level alerts for your saved places and your commute. Without the app, subscribe to the Boston flood calendar and flood days appear on your calendar automatically.
How accurate is the Boston flood forecast?
It's an estimate built from NOAA tide predictions for the Boston station, corrected with live readings from the NOAA Boston gauge, and the measured elevation of every road segment in Boston. Wind, storm surge and blocked drains can change what actually floods. Never drive through flood water.