# Is a Category 6 Hurricane Meteorologically Possible? **URL:** \ **Category:** Factual Questions\ **Tags:** science-math\ **Created:** [October 27, 2025, 12:02pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326 "2025-10-27T12:02:59Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [October 27, 2025, 12:02pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/1 "2025-10-27T12:02:59Z")
This question is derived from Hurricane Melissa, whose strength is shocking given the late time of year. I’m posting this in “Factual Questions” because there are numerous conditions that govern the strength of hurricanes, and I don’t know whether or not those conditions could produce a Category 6 hurricane. ---
**Author:** ![Ponderoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ponderoid/32/19221_2.png) [@Ponderoid](https://boards.straightdope.com/u/Ponderoid)\ **Post date:** [October 27, 2025, 12:04pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/2 "2025-10-27T12:04:18Z")
What is the official definition of a Category 6 Hurricane? ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [October 27, 2025, 12:06pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/3 "2025-10-27T12:06:10Z")
Good question. " **Definition:** A Category 6 would start at winds greater than 192 mph ---
**Author:** ![wolfpup](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolfpup/32/10618_2.png) [@wolfpup](https://boards.straightdope.com/u/wolfpup)\ **Post date:** [October 27, 2025, 12:35pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/4 "2025-10-27T12:35:35Z")
This is not a meteorological question but a definitional one. The Saffir-Simpson scale has no upper limit to Category 5; it’s any hurricane with wind speeds of 157 mph or greater. Maybe in the future if hurricane intensity increases due to much warmer sea surface temperatures caused by climate change, it might make sense to define a new upper category, but no category above 5 exists today. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [October 27, 2025, 12:38pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/5 "2025-10-27T12:38:49Z")
Hypercanes with 500 MPH sustained winds could form given the right conditions, and may have actually formed in the past. (For instance, on a bad day 66 million years ago.) > **[Hypercane](https://en.wikipedia.org/wiki/Hypercane)** > > A hypercane is a hypothetical class of extreme tropical cyclone that could form if sea surface temperatures reached approximately 50 °C (122 °F), which is 12 °C (22 °F) warmer than the warmest ocean temperature ever recorded. Such an increase could be caused by a large asteroid or comet impact, a large supervolcanic eruption, a large submarine flood basalt, or "incredible" global warming. There is some speculation that a series of hypercanes resulting from the impact of a large asteroid or In or... ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [October 27, 2025, 12:40pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/6 "2025-10-27T12:40:10Z")
> [@wolfpup](#): > > Maybe in the future if hurricane intensity increases due to much warmer sea surface temperatures caused by climate change, it might make sense to define a new upper category, but no category above 5 exists today. Rather than trash the question, let’s set that hypothetical speed at 192 MPH. Could conditions on the earth allow for that? For example, I’ve read that straight line winds are limited by the rotational speed of the earth. ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [October 27, 2025, 12:42pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/7 "2025-10-27T12:42:04Z")
I’m interpreting this as, “Yes, but it would take extraordinary circumstances for it to happen.” ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [October 27, 2025, 12:44pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/8 "2025-10-27T12:44:55Z")
> [@Jasmine](#): > > Rather than trash the question, let’s set that hypothetical speed at 192 MPH. Could conditions on the earth allow for that? 215 MPH: > **[Hurricane Patricia](https://en.wikipedia.org/wiki/Hurricane_Patricia)** > > Hurricane Patricia was the most powerful tropical cyclone on record worldwide in terms of maximum sustained winds. It was also the second-most intense on record worldwide in terms of pressure, with a minimum atmospheric pressure of 872 mbar (hPa; 25.75 inHg), just behind Typhoon Tip's 870 mbar. Originating from a sprawling disturbance near the Gulf of Tehuantepec, south of Mexico, in mid-October 2015, Patricia was first classified a tropical depression on October 20. Initial development was sl... ---
**Author:** ![wolfpup](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolfpup/32/10618_2.png) [@wolfpup](https://boards.straightdope.com/u/wolfpup)\ **Post date:** [October 27, 2025, 12:46pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/9 "2025-10-27T12:46:43Z")
Of course, hurricanes are not “straight line winds”. Hurricanes with wind speeds greater than 192 mph have already occurred (e.g.- Patricia in 2015). The real question is how often will these super-strength hurricanes occur, and the answer really hinges on sea surface temperatures, and so the question become one of how soon we can get climate change under control. Climate models tend to show hurricane frequency not necessarily increasing with warming SSTs, but hurricane energy dissipation increasing – i.e.- not necessarily more hurricanes, but stronger ones when they do occur. ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [October 27, 2025, 12:52pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/10 "2025-10-27T12:52:15Z")
Didn’t for some reason know about Patricia and its vast strength, and that’s the kind of fact I was hoping to get. That for sure satisfies my operational definition for this thread of what could be considered a Category 6 (192 MPH), and I agree that only time will tell what will be produced in the future. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [October 27, 2025, 2:36pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/11 "2025-10-27T14:36:07Z")
Now that we’ve mostly addressed the direct FQ … There is an ongoing debate in the NHC and emergency management circles about the whole “Category” system. The short version being that wind speed is a really crappy indication of the hazard severity of a hurricane. Everyone, both sober expert commentators and sensationalist click-baiters, lurve to focus on peak wind speed. That’s not completely irrelevant as to hazard, but it’s a lousy proxy for it. Storm surge height and extent, rainfall rate, speed of storm progress, and lateral size of storm system are all far, far more important to predicting how much stuff will be destroyed, how many people will be killed, etc. So for public warning purposes the S-S Category system ought to be replaced. The challenge is coming up with a replacement that can be based in science, be agreed to, and can be predicted far enough in advance to give a useful warning time. My own bet (assuming NWS is allowed to continue existing at all) is we’ll see a replacement multi-factorial hurricane severity-of-impact scale before we see an S-S Category 6 added on top of the current 5. ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [October 27, 2025, 2:46pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/12 "2025-10-27T14:46:51Z")
> [@LSLGuy](#): > > Storm surge height and extent, rainfall rate, speed of storm progress, and lateral size of storm system are all far, far more important to predicting how much stuff will be destroyed, how many people will be killed, etc. Great stuff, and thank you! ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [October 27, 2025, 3:40pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/13 "2025-10-27T15:40:24Z")
This being FQ, here’s a cite to get you started down the S-S replacement rabbit hole: > **[Wind isn't the only threat: Scientists urge shift to more informed hurricane...](https://phys.org/news/2025-08-isnt-threat-scientists-urge-shift.html)** > > Wind alone does not account for all hurricane-related fatalities. Storm surge and rainfall do as well. Yet the current warning system—the Saffir-Simpson Hurricane Wind Scale—measures a storm's strength solely by wind speed. Here’s another: > **[New Hurricane Rating System Could Replace Saffir-Simpson, Study Says |...](https://weather.com/storms/hurricane/news/2025-09-09-new-hurricane-rating-system-help-people-prepare-better-sooner)** > > Do we need to change the way we rate hurricanes? Researchers seem to think so. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [October 27, 2025, 4:31pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/14 "2025-10-27T16:31:42Z")
With the right thermodynamic conditions there is no physical reason a hurricane can’t grow to any level of power and size short of turbulence conditions causing instability in the central vortex or exceeding the isothermal condition on the inflow. If the outflow at the eye approaches transonic conditions (about Mach 0.8, around 600 mi/hr or 960 km/hr) there would probably be loss of stability of the vortex that would cause a slowdown at the inflow. Stranger ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [October 27, 2025, 4:33pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/15 "2025-10-27T16:33:24Z")
Seems theoretically reasonable so, even though I’m a lowly lay person weather wise, I have to agree. ---
**Author:** ![xtenkfarpl](https://avatars.discourse-cdn.com/v4/letter/x/c2a13f/32.png) [@xtenkfarpl](https://boards.straightdope.com/u/xtenkfarpl)\ **Post date:** [October 27, 2025, 8:43pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/16 "2025-10-27T20:43:20Z")
I guess there is a physical limit to the strength of a hurricane? After all, the air pressure at the center can’t go below zero. Though what it would take to create anything that strong is anyone’s guess…? ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [October 27, 2025, 9:18pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/17 "2025-10-27T21:18:03Z")
For very round numbers, normal surface atmospheric pressure is 30 inHg. A truly monster record-setting hurricane drops the surface pressure in the eye to about 26 inHg. So ~13% below normal. There’s one hell of a lot of room for further pressure drop before zero becomes a limiting factor. The real limiting factors are supersonic flow and the temperature difference between the lower stratosphere & the surface. @Darren_Garrison’s cite upthread to the wiki on Hypercanes is informative if you haven’t read it yet. As is its reference section. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [October 27, 2025, 9:40pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/18 "2025-10-27T21:40:00Z")
[John Barnes’ Mother of Storms](https://en.wikipedia.org/wiki/Mother_of_Storms) is a 1994 novel about a gigantic _supersonic_ hurricane and its spawns menacing the entire world. My memory tells me he spent a lot of time trying to justify such a storm, so it might work as a primer for how superstorms might be possible. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [October 27, 2025, 11:50pm UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/19 "2025-10-27T23:50:49Z")
As it happens I’m rereading that novel right now (read it back in the 'Nineties). Some of the specifics about how ‘Hurricane Clem’ (the megastorm that is spawning other, often larger megastorms) builds and progresses stretches credibility a bit (especially the storm winds reaching supersonic velocities) but it was based upon speculative storm modeling theory at the time. The “clathrate gun” hypothesis for the Late Glacial Interstadial heat anomaly upon which the inciting event for the store (that kicks off massive ocean heating) is been somewhat disproven but we are discovering other unsuspected sources of methane sinks in frozen tundra as well as newer heat-trapping and albedo reducing mechanisms that contribute to global heating today. The potential for year-round hurricanes and typhoons, once thought to be impossible without a massive shift in climate heating, is becoming more plausible, and the typhoon that recently struck the cost of western Alaska further north and such storms usually reach is a harbinger for things to come with climate heating. What is even more interesting about the book, aside form the meteorology and atmospheric thermodynamics, are how accurately the speculations of a lot of the social dynamics and technologies came to pass. We don’t have ‘XV’ (essentially a brain-machine interface for entertainment) or moon bases established and abandoned by many countries, and some of the autonomous technologies and functional AI in the book are beyond the current state of the art, but the author guessed pretty well on a lot of things. (Fortunately Washington DC wasn’t nuked and substantial national autonomy ceded to the UN but the decade is still young.) I’m not a big fan of the third person omnicient narrative style with a continuous narrative not broken by chapters, and constantly creating vignettes developing minor characters only to kill them off a few pages later but the central core of the story is pretty compelling. Stranger ---
**Author:** ![nearwildheaven](https://avatars.discourse-cdn.com/v4/letter/n/90db22/32.png) [@nearwildheaven](https://boards.straightdope.com/u/nearwildheaven)\ **Post date:** [October 28, 2025, 1:57am UTC](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326/20 "2025-10-28T01:57:17Z")
I once participated in a trivia contest where a question about what an EF12 tornado might actually be. None of us knew the exact answer, but we all agreed that if such a thing existed, anyone in the way would be extra F’ed. EF12 is Mach 1. [Next page](https://boards.straightdope.com/t/is-a-category-6-hurricane-meteorologically-possible/1024326.md?page=2)