# Boston flood forecast

Massachusetts

**Clear today** · Next flood window Mon 11:15 AM–12:00 PM

> 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.

- Tide now: 2.8 ft, falling
- Next king tide: Sun, Oct 25, 10:56 AM EDT · 10.8 ft
- Water running +1.1 ft above predicted tides · Boston gauge, 12:00 AM
- Live map and tide scrubber: https://floodroute.com/ma/boston

## Flood windows: next 7 days

| Day | Time | Forecast | Peak tide | Streets |
|---|---|---|---|---|
| [Mon, Oct 26](https://floodroute.com/ma/boston/2026-10-26.md) | 11:15 AM–12:00 PM EDT | Minor flooding possible · king tide | 11.4 ft | Chelsea St, William T. Morrissey Blvd, Marginal St |
| [Tue, Oct 27](https://floodroute.com/ma/boston/2026-10-27.md) | 11:40 AM–1:25 PM EDT | Minor flooding possible · king tide | 11.7 ft | Chelsea St, William T. Morrissey Blvd, Marginal St |
| [Wed, Oct 28](https://floodroute.com/ma/boston/2026-10-28.md) | 12:20–2:20 PM EDT | Minor flooding possible · king tide | 11.7 ft | Chelsea St, William T. Morrissey Blvd, Marginal St |

## Later in the next 30 days

| Day | Time | Forecast | Peak tide | Streets |
|---|---|---|---|---|
| [Thu, Oct 29](https://floodroute.com/ma/boston/2026-10-29.md) | 1:20–2:50 PM EDT | Minor flooding possible · king tide | 11.6 ft | Chelsea St, William T. Morrissey Blvd, Marginal St |
| [Fri, Oct 30](https://floodroute.com/ma/boston/2026-10-30.md) | 2:45–3:00 PM EDT | Minor flooding possible · king tide | 11.3 ft | Chelsea St |

## 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.

**Estimates only.** Never drive through flood water — six inches can float a car. Follow local authorities.

Tide source: [NOAA station 8443970 (Boston)](https://tidesandcurrents.noaa.gov/noaatidepredictions.html?id=8443970). Updated 1:13 AM EDT. Times are America/New York time.

## Calendar, alerts and embeds

- Calendar feed of Boston flood days (iCal, updates itself): https://floodroute.com/cal/ma/boston.ics
- FloodRoute for iPhone (free; Pro adds street-level alerts for your saved places and commute): https://apps.apple.com/app/id6757653475
- Embed this live map on a news or neighborhood site: https://floodroute.com/press#embed

## Frequently asked questions

### 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](https://floodroute.com/ma/boston) 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](https://floodroute.com/ma/boston/2026-10-26).

### 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](https://floodroute.com/cal/ma/boston.ics) 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.

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Web version: https://floodroute.com/ma/boston · Site index for AI agents: https://floodroute.com/llms.txt · Every page is available as Markdown: add `.md` to its URL.

FloodRoute provides estimates only. Never drive or walk through flood water. © Axiomic, LLC · contact@axiomic.ai