"What is the recommended or possible ways to enter the pattern (VFR) when entering opposite from the airport's pattern. For example: coming in from the north to a left pattern on runway 27, both uncontrolled and/or controlled airports." - Jorge B.
“I’m amazed that this question is raised so often. I believe the answer is very straight forward and very safe! Fly directly over the runway, heading toward the downwind at least 1,000 feet above the traffic pattern altitude. You have a perfect view of the airport environment and any approaching aircraft to the airport.
Once clear of the downwind leg, you can start a descending turn to the right to enter the 45 degree entry to midfield downwind. You have already cleared the airspace below you, but always be aware of any arriving aircraft.
Plan to arrive at the 45 degree entry leg at pattern altitude. You do not want to descend upon another aircraft!
I’m a strong believer in flying the standard traffic pattern entry no matter where we are. If we rationalize some other method we are only contributing to confusion in the pattern. If we all fly the standard pattern published in the Aeronautical Information Manual (AIM), we all know what to expect from each other no matter where we are.
At towered airports, comply with the controllers instructions!”