São Mateus do Maranhão, Brazil

What is here

Seven days

The high, the low, the chance and amount of rain and snow, the wind and the forecaster’s words for each day and night, from the National Weather Service grid for the exact cell your town sits in.

Hour by hour

Temperature, what it feels like, dew point, humidity, chance and amount of precipitation, wind and gusts, sky cover, the chance of thunder, pressure, visibility and ceiling, as a chart and as a table, with nights shaded.

Everything else on the grid

The office edits about sixty fields for every cell. The ones the mainstream forecast pages leave out are here as a daily table: HeatRisk, wet bulb globe temperature, lightning activity, mixing height, transport wind, the fire weather indices, and at the coast the waves and swell.

The discussion

The Area Forecast Discussion the forecaster wrote to explain the forecast, in their own words, with the specialist annexes folded away. Also the office’s hazardous weather outlook.

Beyond the week

The Storm Prediction Center’s severe weather category for each of the next eight days, the Weather Prediction Center’s rainfall forecast to day seven and its winter storm severity, and the Climate Prediction Center’s odds for days six to fourteen, all read at your coordinate.

Against the record

Each forecast day beside the same date at the nearest long-record station: the thirty-year normal and the record high and low with their years, so a forecast high that would break a record says so.

The next 90 days

The forecast as far as the grid, the National Blend and the global models reach, and the calendar after that: the normal and the record for every date, with the Climate Prediction Center’s lean for the weeks, the month and the season drawn over them. No made-up highs for a date three months out.

Common questions

Where does this forecast come from?

From the National Weather Service forecast grid published at api.weather.gov, the same grid the local forecast office edits through the day and the source of every forecast on weather.gov. The written periods, the hourly digest and the forecaster’s discussion are the NWS’s own products, shown as issued. Nothing here is a blend a website made.

How far ahead does it go?

The grid runs seven days ahead, hour by hour for the first days and in three to six hour steps after that. The National Blend of Models carries the days to eleven and the global models to sixteen. Beyond that the page carries the national centers’ outlooks, severe weather to day eight, rainfall to day seven, and the Climate Prediction Center’s odds for the coming weeks, month and season, over a ninety-day calendar of the normal and the record for each date. No forecast has skill day by day past about two weeks, and this page does not print one.

Why is this different from the app on my phone?

Most forecast apps show a blend of models chosen by the company that makes the app. This page shows the forecast the local National Weather Service office issues, edited by the forecasters who will also issue the warnings, and it shows all of it rather than the six numbers that fit on a phone. The discussion explains the reasoning, which no app carries.

What is a place’s address here?

Every town has its own page, such as /forecast/us/oklahoma/oklahoma-city/, and every day at a town has one too. A ZIP code typed into the search goes to the town it belongs to. Any coordinate at all can be looked up, and the page names the nearest town.

What the weather actually was · Open the live radar · Where the data comes from