On February 14, 2014, at 1759 central standard time, a Cessna 172M, N194EX, was substantially damaged during a precautionary landing in Pinson, Tennessee. The private pilot/owner was not injured, and the passenger sustained serious injuries. Night instrument meteorological conditions (IMC) prevailed, and no flight plan was filed for the personal flight, which was operated under the provisions of Title 14 Code of Federal Regulations Part 91. The airplane departed Springfield-Branson National Airport, Springfield (SGF), Missouri, with Northwest Alabama Regional Airport (MSL) as the intended destination.The pilot stated that he obtained "all available" current and forecast weather information along the intended route of flight using a commercial weather vendor, and updated his weather information during the flight with air traffic control (ATC) and an on-line commercial weather vendor. The weather conditions at departure were "marginal" visual flight rules (VFR) conditions, and after climbing the airplane to his desired cruising altitude, he was forced to descend due to worsening weather conditions and to maintain VFR. The pilot was advised by ATC that the weather at his intended destination had deteriorated, and provided vectors to a suggested diversionary airport. The pilot turned the airplane to the suggested heading, but continued to descend to maintain VFR. The pilot determined that visual flight could not be continued, and selected a field for a precautionary landing. The airplane subsequently landed hard in muddy terrain, which fractured the empennage and resulted in substantial damage to the right wing. The pilot held a private pilot certificate with a rating for airplane single-engine land. He did not hold an instrument rating. His most recent Federal Aviation Administration (FAA) third class medical certificate was issued February 2013. The pilot reported 150 total hours of flight experience, of which all 150 hours were in the accident airplane make and model. The airplane was manufactured in 1975 and its most recent annual inspection was completed on April 4, 2013, at 2,702 total aircraft hours. The weather reported at McKellar-Sipes Regional Airport (MKL), Jackson, Tennessee, 13 miles north of the accident site, included an overcast ceiling at 1,300 feet with 3 miles visibility in fog. The airplane was recovered from the scene and moved to a recovery facility in Springfield, Tennessee, where postaccident examination was conducted under the supervision of an FAA inspector. The examination revealed there were no preimpact mechanical anomalies that would have precluded normal operation. The pilot seat remained partially attached to its seat tracks with the adjustment pins engaged. The copilot seat was separated from its tracks, and the seat leg "ears" were either splayed open or fractured due to overstress. The seat rails and tracks for both front pilot and copilot seats were inspected for wear in accordance with FAA Airworthiness Directive (AD) Note 11-10-09. Examination and measurement of the dimensions of the seat rails and tracks revealed that they were worn, but did not exceed the allowable tolerances specified in the AD. According to the passenger, she unfastened her seat belt and shoulder harness during the flight to "retrieve a fallen article on the floor of the cockpit." She did not recall if she refastened the seatbelt and shoulder harness. Under the "RECOMMENDATION (How could this accident have been prevented?)" section of the NTSB accident report form, the pilot/owner offered the following: 1. More emphasis was needed on the changing nature of weather conditions, especially on longer leg lengths. 2. The pilot also could have better monitored passenger seatbelt use, especially in low light conditions.