Whether or not global warming is happening, this isn't a scientific statement or really evidence of anything when you think about it.
The warming trends recorded in data would only be noticeable across an entire human lifetime, and human memory is very unreliable on that scale. Even if you had exceptional recall over the course of decades, I'd wager your experience is with local observations (and if it were global, how could you have made observations across decades to notice subtle changes in all locations?). Sales data would absolutely be dominated by other human trends (e.g. population growth, changing tastes, demographics, economic growth, etc). Does this mean you haven't witnessed changes in the environment during your lifetime? Not necessarily. Ecosystem destruction and pollution has been immense in the last ~50 years and is probably far more dominant than global warming effects in your observations.
Unscientific claims from all sides should be discouraged.
You really just can't accept when someone flat out tells you that the numbers don't lie... Amazing. A nationwide business that has shown serious changes that affect sales and... what, it's not acceptable because it isn't over a full lifetime of 70, 80 years and not something that you yourself have observed (not your years, not your observations, not your data)? Did you not read the part where I said "weather directly affects sales?" Weather projections and history are a critical part of this business and are required pieces of data when talking to business partners, banks, and investors and it always has been.
I don't care to try to change your mind. The facts won't change whether or not you believe something.
What business are we talking about? Weather directly affects sales in tons of things (e.g. icecream, oil, boat rentals, vacations, agriculture). But that doesn't mean climate change would be visible in sales data since this data will be noisy and and interest rates, economic growth, and hundreds of other variables will have a far greater impact. It's a very bold claim that you can see evidence of global warming in sales data.
I love it how people try to tell me that we're absolutely not experiencing a global warming. I work in an industry that is directly influenced by how warm the winters are. I see the data and the numbers and sales. It's getting warmer every year.