It's common for cats to resist wearing a harness and going for walks, as it's a new and potentially uncomfortable experience for them. With your patience and proper training, many cats can be acclimated to harnesses and enjoy outdoor adventures.
Your cat might be too scared to go on walks. Some cats just don’t like it. If your cat is already interested in walking outside, you can try to harness train. Don’t try to force your cat to walk outside if it doesn’t want to.
Remember that not all cats will enjoy outdoor walks, and some may never become comfortable with a harness. Always prioritize your cat's comfort and well-being. If your cat consistently resists the harness despite your efforts, consider providing alternative forms of indoor enrichment to keep them mentally and physically stimulated.
I personally take 2/3 of my cats on walks. I live in Arizona, so it’s too hot sometimes, but I try to do it every day for at least 30mins.
In my experience, they don’t like areas that are open fields. They don’t like grassy parks or open areas without hiding spaces. If you take them to a grassy area, they will might just crawl on the ground because they feel exposed.
Take them somewhere with walls and paths to follow.
Here are some resources I think will help: