How accurate is the forecast?
The National Weather Service misses the daily high by 2.26°F the same day and 4.38°F 6 days out · 389 towns · since Aug 15, 2026
Everyone has an opinion. Almost nobody checks, because checking means writing the forecast down before the day arrives - and the Weather Service only ever publishes the current one. So we keep the receipts: every day we archive the forecast for 389 towns, and afterwards we compare it against what the nearest weather station actually recorded.
This measures the National Weather Service, not anyone who publishes here. Nobody on Forecaster HQ is graded, ranked or badged by this page; it is the public forecast every forecaster starts from, checked in the open.
Days checked
100,212
Towns
389
Since
Aug 15, 2026
Station distance
4.8 mi
Today’s forecast misses the daily high by 2.26°F on average, and the forecast made 6 days ahead misses by 4.38°F. Set aside the fixed gap between each town and the weather station measuring it, and the forecasting alone accounts for 2.08°F and 4.14°F. The forecast made 2 days ahead landed within 3°F of the high 71 times in a hundred.
| Made | Miss | Forecasting alone | Low | Days checked |
|---|---|---|---|---|
| Same day | 2.3°F | 2.1°F | 3.9°F | 15,572 |
| 1 day ahead | 2.6°F | 2.5°F | 3.9°F | 15,185 |
| 2 days ahead | 3.0°F | 2.7°F | 3.9°F | 14,796 |
| 3 days ahead | 3.3°F | 3.0°F | 4.0°F | 14,414 |
| 4 days ahead | 3.8°F | 3.5°F | 4.1°F | 14,028 |
| 5 days ahead | 4.3°F | 4.0°F | 4.3°F | 13,640 |
| 6 days ahead | 4.4°F | 4.1°F | 6.1°F | 11,910 |
What this does and does not say
This measures the National Weather Service, not us. We archive their forecast; we are not grading our own homework. The Weather Service is very good at this, and the numbers above are better than most people assume - a two-day-out forecast landing within 3°F most of the time is a real achievement.
Some of the miss is not forecasting at all. Outcomes come from the nearest automated station, usually at an airport - the same instruments the official daily high and low come from. But the forecast describes the town, and the thermometer sits somewhere else: the median town here is 4.8 miles from the station grading it. In about a third of towns the error never changes sign across the whole record, which is not a forecast getting things wrong - it is two places with different weather. That gap widens with distance, from under two degrees within five miles to over four beyond twenty. The “forecasting alone” column removes each town’s own offset and is the fairer measure of skill.
A day is only graded once it has ended everywhere. A station’s summary for the current day reports the highest reading so far, not the day’s high, so grading against it makes every forecast look badly wrong. Nothing here is scored until the day is complete in every time zone.
The lead times are not measuring the same days. A forecast six days ahead can only be graded for dates at least six days after the archive began, so each column covers a slightly different stretch of weather. That is why the six-day figure can sit below the five-day one rather than continuing to climb: it is a smaller sample of different days, not evidence that forecasting further out is easier. Comparisons between adjacent columns are weaker than the overall shape, and both will firm up as the record lengthens.
The record is young. It starts on Aug 15, 2026, so this is one stretch of weather in one season, not a verdict on the whole year. Forecasts are easier in a settled pattern than in an unsettled one, and this page will get more honest as the archive lengthens. Lead times with too few graded days are left blank rather than filled with a number that would only get quoted without its caveat.
Sources: forecasts from the National Weather Service, archived daily. Observations from the Iowa Environmental Mesonet’s summaries of ASOS data. Coastline from Natural Earth. Updated daily.