 While trekking across the central Caribbean Sea , Janet was only slightly larger than while it was moving over the Windward Islands , with gale force winds extending 125 mi ( 200 km ) out from the center by September 25 . Remaining a Category 4 hurricane as it moved erratically westward across the Caribbean , a reconnaissance flight mission during the night of September 25 – 26 indicated strong rainbands with frequent lightning strikes and a well @-@ defined eye , evidence that the storm was once again rapidly intensifying . As it neared the Yucatán Peninsula on September 26 , Janet began accelerating in forward speed . After the reconnaissance flight Snowcloud Five was lost while making a penetration into the hurricane 's eye , another flight early on September 27 reported a minimum pressure of 938 mbar ( hPa ; 27 @.@ 70 inHg ) , with winds in excess of 115 mph ( 185 km / h ) " by a large and incalculable amount . " The hurricane was estimated to have intensified to Category 5 hurricane intensity — the highest rating on the modern day Saffir – Simpson hurricane scale — at 1200 UTC on September 27 , while in the western Caribbean Sea . Janet continued to intensify afterwards , eventually reaching its peak intensity with maximum sustained winds of 175 mph ( 280 km / h ) , with gale force winds having expanded to at least 250 mi ( 400 km ) away from the center of the hurricane . Janet maintained peak intensity as it passed over the Swan Islands before making landfall in extreme southern Quintana Roo , Mexico , just east of Chetumal , Mexico . In that city , a barometer indicated a minimum barometric pressure of 914 mbar ( hPa ; 27 @.@ 00 inHg ) in the eye of Janet . At the time , this was the second lowest pressure ever recorded on land in a landfalling Atlantic hurricane , behind the 1935 Labor Day Hurricane , though Janet was later surpassed by hurricanes Dean and Gilbert , which also made landfall on the Yucatán Peninsula as Category 5 hurricanes . 
