There's definitely a limit to how far ahead they're likely to be accurate, I have to laugh when people start to tell me that we're likely to have a hard winter, months ahead. At the moment I'm just living in hope that we have an unexpected cooler day!
They don't seem to tell you much about humidity, which makes a big difference to my comfort. There was one day this week which was no cooler than others but a slight breeze and lower humidity which made it bearable.
I was out babysitting last night and really enjoyed the short walk home in the cool breeze at midnight. I opened the windows when I got home and our house was lovely and cool first thing, which hasn't happened for some time.