Storm Dennis was a European windstorm which, in February 2020, became one of the most intense extratropical cyclones ever recorded, reaching a minimum central pressure of 920 millibars (27.17 inches of mercury). The thirteenth named storm of the 2019–20 European windstorm season, Dennis affected the Republic of Ireland and the United Kingdom less than a week after Storm Ciara, exacerbating the impacts from that storm amidst ongoing flooding in the latter country.