What does normal high temperature mean?

It is the average high for that date across a thirty year period, currently 1991 to 2020, recalculated each decade. It is a midpoint, not the temperature to expect.

How are daily temperature records set?

A record is the most extreme value observed on that calendar date at a specific observing station, over however long that station has kept records.

Is a day above the normal high unusual?

Not necessarily. Roughly half of days are above the normal, since it is an average. What makes a day unusual is how close it sits to the record for that date.

Is today unusual for this date?

People ask whether a day is hot. The more interesting question is whether it is hot for this particular date in this particular place, and that needs two numbers almost nobody is shown.

Normal does not mean typical

A normal high is an average, and specifically an average over a thirty year period that is recalculated every decade. The current set covers 1991 to 2020. So the normal high for a date is not the temperature you should expect; it is the middle of a range that may be very wide.

This matters because a day can sit several degrees above normal and still be completely ordinary for the date, while in a different season the same gap would be remarkable. Normals in spring and autumn move quickly; in midsummer and midwinter they barely move at all.

What a record actually is

A record high for a date is the warmest that date has ever been at that observing station, over the period the station has been keeping records. That last clause carries a lot of weight. A station with a century of data and a station opened in 1998 will produce very different looking records, and neither is wrong.

Records also belong to a specific place, usually an airport, not to a city as a whole. The reading that breaks a record is the one at that instrument.

The comparison worth making

Put today's reading on the same scale as the normal high and the record high and low for the date, and the answer becomes visual. A day sitting just above the normal is ordinary. A day pressed up against the record end of the scale is genuinely unusual, and you can see it without doing arithmetic.

That comparison is the reason this site shows all four numbers together rather than a temperature on its own.

Common questions

What does normal high temperature mean?: It is the average high for that date across a thirty year period, currently 1991 to 2020, recalculated each decade. It is a midpoint, not the temperature to expect.
How are daily temperature records set?: A record is the most extreme value observed on that calendar date at a specific observing station, over however long that station has kept records.
Is a day above the normal high unusual?: Not necessarily. Roughly half of days are above the normal, since it is an average. What makes a day unusual is how close it sits to the record for that date.

The board places the current reading on one scale with the normal high and the record high and low for the date.

See today against the record book

Related guides

Categories and definitions on this page follow the National Weather Service and the Storm Prediction Center. For the official text of any product in effect, see weather.gov.