Date: 202008
Local time of day: 1201-1800
Location: ZZZ.TRACON, US
Flight conditions: Marginal
Weather elements / visibility: Haze / Smoke; 3
Light: Daylight
Aircraft: Skyhawk 172/Cutlass 172
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Personal
Flight phase: Cruise
Airspace: Class E ZZZ
Reporter organization: Personal
Reporter function: Pilot Flying; Single Pilot
Reporter qualification: Flight Crew Private
Human factors: Training / Qualification; Time Pressure; Situational Awareness
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter VFR In IMC; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Diverted
Contributing factors: Weather; Human Factors
Primary problem: Weather

Narrative: The out-bound trip from ZZZ2 to ZZZ4 at 7500 ft. MSL in the morning local was VMC/MVMC due to wildfire smoke in the area. Horizon was visible the whole way. Nothing of particular concern from the multiple weather briefings prior to the flight except for possibility of low cloud coverage along the coast near the ZZZ4 destination. TAFs showed VFR (Visual Flight Rules) at time of arrival. TAFs were not as forecasted; so we made a diversion to ZZZ3 and landed long enough to re-fuel and use the facilities. Combined with a later than desired departure; we were now under a slight time crunch to get the plane back to base for the next renter. No weather briefing was obtained prior to return flight.An hour later; departing on the return flight from ZZZ3 to ZZZ2 at 6500 ft. MSL; weather was still MVMC forward but ground was clearly visible. Departure and destination airport METARs showed VMC. About 30 nm out from our destination; I noticed the horizon ahead appeared slightly orange in color. A few minutes later I noticed visibility decreasing and we began to smell smoke from the fires outside. We were on VFR flight following and I heard a pilot say they were encountering smoke as well and they were able to break out at 8500 ft. above the smoke. I notified ATC of my intent to climb to 8500 ft. and asked for clearance into the ZZZ1 class B. I was aware of the firefighting TFR (Temporary Flight Restriction) (up to 7000 ft.) to my right; ZZZ4 class C to my left; and ZZZ1 class B ahead. During the climb to 8500 ft.; I lost visibility to the ground and switched to instrument flying. Now near 8500 ft. and still not clear of the smoke; I informed ATC of my planned descent to 4500 ft. Now lower; I re-acquired visual with the ground and the parallel runways of ZZZ. I informed ATC of my desire to divert to ZZZ due to limited visibility over the hills to ZZZ2.We landed at ZZZ and I called my flight club to inform them of the situation and waited for an instrument-rated instructor to help me fly the plane back to base at ZZZ2. We filed IFR (Instrument Flight Rules) and I completed the return-to-base flight; again in the smoke; but on a filed and cleared IFR flight plan with an instructor.What surprised me was how misleading smoke can be because it doesn't seem to affect the reported weather conditions at nearby airfields other than the words 'smoke; haze'. No accurate information; besides PIREPs (Pilot Reports); is available regarding ceilings or actual visibility. In fact; all the airports near ZZZ and ZZZ2 were showing VFR conditions.Because this trip involved a longer cross-country than I usually fly; it's especially important to get a weather briefing for the return trip; or each leg as the case may be. One can't assume conditions are basically the same as the outbound flight. Most importantly; however; was my potentially deadly decision to not declare an emergency and attempt a 180 and hopefully return to VMC. Although I'm not yet an instrument rated pilot; at the time of this incident I was in training and had about 22 hours of instrument time and was comfortable enough in the situation to get out of it safely. However; that doesn't legally matter because I wasn't on an IFR flight plan and I'm not rated.In the future as a VFR-only pilot; I will be much more cautious about flying in haze and smoke because airport weather stations don't quantify the situation. I now know that an orange colored horizon ahead means turn around; divert; or land as soon as possible. I will also take the time to get a proper weather briefing for quick turn-around trips even if it means the next person to rent the plane may have to delay or cancel.




Synopsis: Private pilot flying C-172 reported entering instrument meteorological conditions due to smoke from nearby wildfires.