Pilots will tell you they'd rather be down here wishing they were up there than up there wishing they were down here. (See also, "All takeoffs are optional; all landings are mandatory.") Most of the time it's an easy choice for private pilots whether to go for a flight, especially in Chicago where the weather, not to put too fine a point on it, often sucks.
Today, I had scheduled a flight, but I decided to stay on the ground after thinking really hard about it. Right now Chicago Executive reports scattered clouds at 3600 ft and a medium (9 kt) breeze; nothing I can't handle. However, the forecast calls for gusts to increase to 18 kt, thickening clouds, and the possibility of thunderstorms this afternoon.
Today's mission, though, was simply to fly up to Waukegan or Kenosha, shoot some landings, and return. Today's weather forecast ordinarily wouldn't stop the flight, because as the weather deteriorates, I only have to fly 15 minutes and be home. Not to mention, I'll never be more than 6 minutes from an airport, as the whole point of the flight is to practice landings.
So why stay on the ground? Because I decided I didn't meet the IM-SAFE checklist. Here's how it went: Illness, no; Medication that causes physical impairment, no; Stress, hmmm; Alcohol, no (nor its effects—the FAA considers "under the influence" to include a hangover, even with a zero blood-alcohol content); Fatigue, hmmm again; Emotion: not an issue.
See, today, I'm thinking about the stack of reading materials for Duke on top of a lot of client work due this week, and even though I got a good night's sleep, I feel like I could have gotten more. Am I safe to fly around the airport and practice landings feeling like this? Yes, I believe I would be—if the weather were perfect. But the winds and clouds are going to increase while I'm getting fatigued from all those landings, which means each landing will be much harder than the last one. That means I probably won't learn from them, I'll probably start to get frustrated, and then by the time I return to Chicago Executive I'll be cranky, tired, and fighting gusty crosswinds while trying to get an aluminum tube to fall 500 m out of the sky so gently that someone can use it again. Not to mention, it's an hour-long drive each way, two hours in which I could be writing for clients or reading for school.
So it's a very tough call, and I'd really like be up there today. Just not enough to risk wasting the trip.