Sure, there are some states where the weather is fairly uniform. Still, even a dinky little state like Massachusetts has _very_ significant differences in weather; the eastern end is on the coast and the western end is 140 miles inland. You don't think of Wisconsin as a big state, yet Northern Wisconsin is significantly colder than Southern Wisconsin, and there are differences in the native plant and animal species because of it.
California is smaller than Texas in area but is huge in its linear extent: almost 800 miles from north to south; and it has huge differences in elevation.
When I visited Texas I was interested to see that the newspapers and television stations give five separate weather reports for different regions.