Traders see little chance Bertha reaches hurricane strength

Tropical Storm Bertha is moving near the northern Gulf Coast with maximum sustained winds near 60 mph. Traders give Category 1 or above only about a 5% chance — and leave Category 2 or above at about 2%.

How this market pays

You’re betting on how strong Tropical Storm Bertha gets before it is done — measured by its peak maximum sustained winds in the National Hurricane Center’s reports. Each line in the table is its own Yes/No bet on whether the storm ever clears that wind speed, not a single race where only one winner gets paid. So if Bertha’s peak is later listed at 100 mph, Category 1 or above and Category 2 or above can both pay Yes on that same peak.

Kalshi confirms the peak from NOAA’s National Hurricane Center. If Bertha reaches a threshold before December 1, 2026, that bet can pay on the first 10:00 a.m. Eastern morning after the Center reports it.

How to look at each side

The case for Category 1 or above. A Category 1 hurricane needs sustained winds of at least 74 mph. Overnight into July 21, Bertha’s center sat exposed with little thunderstorm cover. By mid-morning, new storms had rebuilt closer to the center, and Air Force Hurricane Hunter aircraft found stronger winds higher up, southeast of the storm’s center — enough for the National Hurricane Center to raise the storm to 60 mph. The Center’s 1 p.m. CDT intermediate advisory on July 21 still lists 60 mph, 14 mph short of hurricane strength. That is the Category 1 case at 5%: Bertha has already shown it can tighten up after looking ragged, so the remaining gap is one more solid strengthening burst — not a climb from a weak, disorganized system.

The case for Category 2 or above. Category 2 needs peak sustained winds of at least 96 mph — 22 mph beyond the Category 1 floor, and 36 mph above the July 21 reading of 60 mph. If Bertha’s peak later clears 96 mph, the Category 1 bet wins on that same peak too. Traders price the harder clear at about 2%. The Category 2 case needs Bertha not only to reach hurricane strength but to keep strengthening while the National Hurricane Center’s own multi-day forecast instead shows gradual weakening as the storm moves near or along the northern Gulf Coast.

What the odds are saying

Traders put about a 5% chance on Bertha ever reaching hurricane strength — and about a 95% chance its peak stays below 74 mph.

Category 1 or above sits at 5%. Category 2 or above is 2%. Category 3, 4, and 5 or above each trade at about 1%. The biggest step is the first one: whether Bertha becomes a hurricane at all.

That 5% lines up with the National Hurricane Center’s written forecast discussion on July 21: the official numbers keep Bertha at 60 mph through Tuesday night, then step down to 50, 45, 40, 35, and 30 mph before the storm is called no longer tropical and inland, then dissipated — with no forecast hour at or above 74 mph.

2 reasons Category 1’s 5% chance can still move:

1. The official forecast can miss a short burst. The National Hurricane Center already raised Bertha to 60 mph on the morning of July 21 after Hurricane Hunter data and rebuilding thunderstorms. A similar burst that adds another 15 mph before the storm feels much land or disruptive high-altitude winds would clear 74 mph even if the multi-day weakening path still looks right later.
2. Time over open Gulf water. The July 21 discussion notes that forecast models disagree on how much Bertha brushes southeastern Louisiana, and whether a new storm center could form farther offshore. More hours with the storm’s core over warm Gulf water keep open a strengthening window that a land-heavy path would close.

What to watch

National Hurricane Center advisories as Bertha moves near or along the northern Gulf Coast through Thursday, then toward Texas, with the July 21 forecast calling for dissipation by Saturday, July 25.