I assume you mean that your tread depth is 4/32 now. Even though the legal limit is 2/32, my opinion is that anything below 4/32 is unsafe in rain and anything below 6/32 is unsafe in snow. Also, there’s the issue that your tires are getting old. Tire Rack found that the lifetime of a tire is six to ten years depending on various factors. If this were my car, I’d replace the tires now.
If it was my car in your conditions I would probably let it go, though, I would have to recommend for someone else like you, time to consider replacements if economically feasible.
Suggestion: check the date codes (week/year) on the tires. They might be older than 8 years which might affect your considerations.
Personally, I have a 10 year limit, which can be lower depending on the car and the driving conditions and habits. Driving in northern CA in mountains and with rain/snow is very different from southern CA with dry conditions.
The history of where the tires were up until now may also matter. The rubber hardens no matter what, but it can harden faster/slower depending on conditions.
Tires possibly 8 years old, not holding air as well now, close to replacement wear, sounds like a no brainer to me. Look for tires now before you have failure in some place really inconvenient or unsafe.