Narrative:

I was on a solo cross country. All forecasts showed overcast clouds at 6;000 ft. My route was 4;500 ft. [Outbound] and 3;500 ft. On the return flight. [Enroute] I realized the clouds were not at 6;000 ft. As forecast. I continued as I was still under the cloud level; just inland I contacted departure that I was descending down to 4;000 ft. To continue VFR. As I descended the clouds descended with me. Just a few miles into the land I flew into a cloud accidentally as the layer was much lower. I then put the pitot heat and carb heat on and descended out of the cloud. At 2;500 ft. I came out of the cloud [and] noticed the visibility wasn't much better and the field might go IFR soon. [I] also noticed visible moisture on the windshield and texted my instructor that I had possible icing and that I was returning to [home base]. I then contacted approach saying I was [experiencing] possible icing. They then gave me straight into the runway with no delay. Thankfully I was first in line and didn't need to declare an emergency. I flew straight towards [the airport] and rounded off my approach for the shortest distance. I put ten degrees of flaps in and kept my airspeed at 90 until I was within range of [the airport]; coming in faster and a bit high to ensure not needing a go-around. Once over the runway I pulled the power and dumped in full flaps; landed safely and taxied to [the ramp]. Once back I showed my instructor the icing and discovered moderate mixed icing along all leading edges. I was able to stay calm and make a quick decision; with the help of my instructor's instructions to this point. This experience was very humbling and the decision to go was probably wrong but I trusted the forecast.

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Original NASA ASRS Text

Title: C172 student pilot reported returning to departure airport after encountering unforecast icing conditions.

Narrative: I was on a solo cross country. All forecasts showed overcast clouds at 6;000 ft. my route was 4;500 ft. [outbound] and 3;500 ft. on the return flight. [Enroute] I realized the clouds were not at 6;000 ft. as forecast. I continued as I was still under the cloud level; just inland I contacted Departure that I was descending down to 4;000 ft. to continue VFR. As I descended the clouds descended with me. Just a few miles into the land I flew into a cloud accidentally as the layer was much lower. I then put the pitot heat and carb heat on and descended out of the cloud. At 2;500 ft. I came out of the cloud [and] noticed the visibility wasn't much better and the field might go IFR soon. [I] also noticed visible moisture on the windshield and texted my instructor that I had possible icing and that I was returning to [home base]. I then contacted Approach saying I was [experiencing] possible icing. They then gave me straight into the runway with no delay. Thankfully I was first in line and didn't need to declare an emergency. I flew straight towards [the airport] and rounded off my approach for the shortest distance. I put ten degrees of flaps in and kept my airspeed at 90 until I was within range of [the airport]; coming in faster and a bit high to ensure not needing a go-around. Once over the runway I pulled the power and dumped in full flaps; landed safely and taxied to [the ramp]. Once back I showed my instructor the icing and discovered moderate mixed icing along all leading edges. I was able to stay calm and make a quick decision; with the help of my instructor's instructions to this point. This experience was very humbling and the decision to go was probably wrong but I trusted the forecast.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.