How to read the hurricane cone of uncertainty
“Cone of uncertainty” is the everyday name for what the National Hurricane Center calls the track forecast cone. It shows the probable track of a storm’s center, sized so the center stays inside it about two-thirds of the time. It says nothing about how big the storm is or where its impacts will reach.
What the cone shows
NHC forecasts where a storm’s center will be at 12, 24, 36, 48, 60, 72, 96 and 120 hours. Around each forecast point it draws a circle, and the track forecast cone is the area those circles sweep out. The size of each circle is not a guess about this particular storm: it is set so that two-thirds of NHC’s official track errors from the previous five years would fall inside it. NHC has built the cone this way since 2007.
So, based on recent history, the storm’s center should stay inside the cone roughly two times out of three, and fall outside it about one time in three.
What the cone does not show
- The size of the storm. The cone is about the path of the center. A large hurricane can bring damaging winds far beyond the cone’s edge.
- Where the impacts will be. Storm surge, flooding rain and tornadoes routinely happen outside the cone, sometimes well away from the landfall point.
- Intensity. A narrow cone does not mean a weak storm, and a wide cone does not mean a strong one.
On HurriTracker storm pages, the separate wind-field layer shows how far tropical-storm and hurricane-force winds reach right now, and colored coastlines show watches and warnings. Those, not the cone, tell you who is under threat.
How wide is the cone of uncertainty? Sizes by forecast day
These are NHC’s 2026 circle radii, based on its 2021–2025 track errors. The width of the cone at each forecast hour is twice the radius. From 24 hours on, the Atlantic circles are larger than the Pacific ones because NHC’s recent Atlantic errors were larger.
| Forecast hour | Atlantic radius | Atlantic width | E. & C. Pacific radius | E. & C. Pacific width |
|---|---|---|---|---|
| 12 h | 25 n mi | 60 mi / 95 km | 25 n mi | 60 mi / 95 km |
| 24 h (day 1) | 39 n mi | 90 mi / 140 km | 37 n mi | 85 mi / 140 km |
| 36 h | 49 n mi | 110 mi / 180 km | 48 n mi | 110 mi / 180 km |
| 48 h (day 2) | 62 n mi | 140 mi / 230 km | 56 n mi | 130 mi / 210 km |
| 60 h | 77 n mi | 180 mi / 290 km | 66 n mi | 150 mi / 240 km |
| 72 h (day 3) | 95 n mi | 220 mi / 350 km | 78 n mi | 180 mi / 290 km |
| 96 h (day 4) | 134 n mi | 310 mi / 500 km | 106 n mi | 240 mi / 390 km |
| 120 h (day 5) | 200 n mi | 460 mi / 740 km | 138 n mi | 320 mi / 510 km |
Source: NHC, Definition of the NHC Track Forecast Cone (2026). Radii in nautical miles; widths converted to statute miles and kilometres.
The cone right now
Measured from the latest cone NHC published for each active storm below. Each width is the distance across NHC’s circle at that forecast hour, taken from the cone polygon itself.
- Hurricane Rachel (advisory 17): 85 miles (140 km) wide at day 1, 180 miles (290 km) wide at day 3 and 320 miles (510 km) wide at day 5. The cone runs 660 miles (1,060 km) from the storm’s position to its last forecast point.
- Tropical Storm Nolo (advisory 43): 85 miles (140 km) wide at day 1, 180 miles (290 km) wide at day 3 and 320 miles (510 km) wide at day 5. The cone runs 1,530 miles (2,460 km) from the storm’s position to its last forecast point.
- Tropical Depression Nineteen-E (advisory 8): 85 miles (130 km) wide at day 1. The cone runs 300 miles (480 km) from the storm’s position to its last forecast point. NHC’s forecast for it ends at 24 hours.
Every circle measured here is within 2 nautical miles of the size in NHC’s 2026 table above: the cone on the map is built from exactly those circles.
Why you should not focus on the center line
The line through the middle of the cone is NHC’s best estimate, but it is only the most likely of many possible tracks. By day 3 the Atlantic circle has a radius of 95 nautical miles (about 110 miles), so the cone there is about 220 miles across, and a landfall anywhere inside it is well within normal forecast error. Being on the center line does not mean the worst will hit you, and being near the edge does not mean you will be spared. Prepare as if you could be anywhere in the cone, and follow the watches and warnings for your area.
Why the cone keeps getting narrower
NHC recalculates the circle sizes before every season from its latest five years of official track errors; the 2026 circles come from the 2021–2025 errors. It uses five years because a single year’s errors swing with the kind of season: years dominated by storms moving through the steady trade winds have small errors, while years with many storms in the mid-latitude westerlies, as can happen in El Niño years, have larger ones.
As forecasts improve, the circles shrink. NHC’s verification report on the 2025 season says its track skill is near historical highs, with substantial long-term improvement continuing at every forecast time. Model plots, often called spaghetti models, show a different kind of uncertainty: how much today’s models disagree about this one storm.
Cone of uncertainty FAQ
What does cone of uncertainty mean?
It is the everyday name for NHC’s track forecast cone. The uncertainty is about where the storm’s center will go, not how strong or how large the storm will be. A wide cone means the center’s future position is less certain; it does not mean the storm is bigger or that places inside it face more danger.
Is there a new hurricane cone for 2026?
Yes, in two ways. The operational cone uses new circle sizes each season, and the 2026 circles come from NHC’s 2021–2025 track errors. NHC is also testing an experimental cone in 2026, built from ellipses that cover 90% of past along-track and cross-track errors. It is issued alongside the operational cone, and NWS takes comments until November 30, 2026.
If I am outside the cone, am I safe?
Not necessarily. The center leaves the cone roughly one time in three, and hurricane-force winds, storm surge, heavy rain and tornadoes often reach well beyond it. Follow the watches and warnings for your own area rather than the cone’s edge, and know your evacuation zone before a storm threatens.
Why does the cone get wider?
Because forecast errors grow with time. A small error in how fast or in which direction a storm moves today adds up over five days, and the steering winds themselves are harder to predict further ahead. NHC sizes each circle from its past errors at that forecast hour, so the circles, and the cone, widen with lead time.