PA28 pilot reported departing on the wrong frequency resulting in a NMAC with another aircraft that was landing in the opposite direction.

Narrative

I taxied for takeoff and checked the windsock. It indicated a slight south wind. I pulled up AWOS and confirmed about 3 knots from a southerly direction. I announced on the radio my intention to depart south. I did not hear any radio traffic; so I proceeded to my run up and then announced departure on runway XX; straight out. I checked for traffic and observed no one downwind or base and took off. As I rotated and climbed out I saw an airplane just touching down in the opposite direction runway XY. I looked at my radio and realized I had not switched from AWOS to CTAF so none of my radio calls had been heard and an airplane had entered the pattern unbeknownst to me.My error was the failure to switch to the proper CTAF frequency so anyone in the pattern knew my intentions and scanning the pattern more thoroughly to the south for possible traffic. The correct action is to verify and ensure you are on CTAF at all times during taxi; run up and takeoff; listen for traffic and confirm intentions of all traffic within and approaching the traffic pattern.