A general aviation pilot reported VFR flight into IMC. Pilot contacted ATC and diverted to an alternate field and landed safely.

Narrative

I departed for a VFR flight to ZZZ airport from Summerville Airport (DYB) in Aircraft X. The flight was a solo night cross-country for my commercial training. I was initially planning to go to CRE but decided to head south to ZZZ instead because the weather up north was questionable. This was confirmed during my two calls to Flight Service. I cruised over to ZZZ at 4;500 with forecasted weather pure VFR from the night to the early morning. The flight was uneventful until I got about 30 miles from ZZZ when approach notified me that the field had just gone IFR unexpectedly. I requested to divert to ZZZ1. The controller notified me that weather was VFR and I confirmed this with their automated weather system as well. Getting closer to ZZZ1; I saw thin wisps of clouds and was unable to find the field so I told approach I would just head back to Summerville as I didn't want to get boxed in with weather. I went back to Summerville at 5;500 and could see that a few wisps of fog were already forming over towns and buildings on the surface. However; conditions were still perfect VFR but I wanted to get back as soon as possible as I had a feeling that the weather was going to change very rapidly. Getting closer to Summerville; I saw the beacon but could see that a wisp of fog was partly obscuring it. However; I could see part of the runway lights and the ASOS was reporting ceilings at 12;000 and 10 statute miles of visibility. I cancelled flight following with CHS and entered a left downwind for runway 24. At this time; I lost visual contact with the field and saw that the fog had already become worse in a matter of minutes. After turning base; I went missed and attempted to get my bearings as I had no reference if I was over the field or not. I realized that I was actually left of the field and corrected back onto a runway heading. I listened to the ASOS again and now it was reporting a scattered layer at 500. I knew that other airports in the area such as JZI; LRO; MKS were solid IFR. I had heard reports that the weather was moving in around the coast so I figured CHS was also IFR as well so I figured Summerville was my best option as it was still VFR and I hoped I could find a hole and just dodge the clouds. My first priority was getting down ASAP so I loaded up the RNAV 06 LPV approach. I planned to use this for guidance purposes as the field was now completely obscured. I am not instrument rated but was only 2 weeks from my checkride so I knew how to load and execute the approach as I had flown it multiple times. I again listened to the weather and it was still VFR but now overcast at 500. As previously stated; I knew that basically everywhere else was IFR and assumed CHS was too because of its proximity to the coast. I knew that even if I had to get into the clouds this was my only option to get down before the field became LIFR. I set up and flew the approach fine. Upon getting to 500 feet AGL I entered the cloud layer. I was in and out of IFR conditions for a few seconds and combined with mild turbulence and I ended up losing the glide slope and lateral course. The minimums for the approach were 253 and when I broke out my altimeter said 260 so I knew the clouds had dropped to 300 feet in a matter of maybe 2 minutes. Despite the airport lights being on previously; and having keyed the mic multiple times; the lights were not on and would not turn on when I broke out. I knew I was far right of course having gotten mildly spatially disoriented in the quick decent through the clouds. I saw the beacon and the hangars but no runway lights. I knew there were trees all around the field and a tower off to the left. I was obviously stressed and had a 'what do I do' moment for a couple of seconds. My training kicked in and I immediately knew I had to go around and get out of there. I climbed back up through the cloud layer to VFR at 2500 and called up CHS approach. I advised them of my situation and that I was basically boxed in. The controller checked to see if weather was agreeable at MKS; Moncks Corner; only a few miles away; but conditions there were LIFR and I advised him that I could see from where I was that the field was completely covered. He decided to have me divert to CHS as weather conditions were actually still VFR there but rapidly deteriorating. They cleared me to land any runway and turned the lights up full blast. I was able to make a visual approach to runway 15 going through a fast-closing hole in a layer of clouds at 700 feet. I landed uneventfully and within minutes; the clouds dropped to ground-level and the airport went to LIFR. Overall; I don't think anything could have been done to prevent this situation unfortunately as the weather did a complete unforecasted 180. In hindsight; I believe that diverting to Charleston after trying to make the visual approach to Summerville would have been the better plan; but from my vantage point; it looked like Charleston was IFR. I understand that by legal definition I should not have been in the clouds; even as brief as it was; however my priority was getting the plane down safely and it was really a choice of 2 not-so-great options: stay airborne with a threat of the weather actually becoming worse; or take the chance and go through a small pocket of clouds while the weather was still 'better'.