I am asked frequently by friends, co-workers, and family, on a somewhat cloudy/rainy day, "Could you fly in this?", but I usually change the question on them to "Would you fly in this?", as many times it would be legal to fly, but that doesn’t necessarily mean I myself would fly in those conditions. Pilots often set standards, minimums, and rules on themselves that are higher and more strict than the FAA imposes on them, and these are called "Personal Minimums."
As far as aviation goes, Personal Minimums can be anything from weather like "I must have at least a 2000′ ceiling and 6 miles visibility to leave the traffic pattern, no crosswind components above 15 knots for landings" to things like "I will not fly a single engine airplane IFR over the mountains" to "I will not fly a single engine rental airplane IFR" to "when crossing the mountains I will fly a route that follows a major road" to "I will always carry a survival kit and a handheld radio with me when I fly"
Personal Minimums are a good idea, and one shouldn’t be ashamed that they are more strict than what the FAA imposes. They are a good measure of what you are comfortable doing in an airplane, and when you know you should start to feel uncomfortable. I don’t know many people that think flying in weather that is 1000′ ceiling and 3 miles visibility, the FAA VFR minimums, is a good idea, and most will say it is a bad idea.
I am also not saying that once you get your certificate that you set your personal minimums and they stay fixed for the duration of your aviation career. In fact, they should be constantly evaluated and changed to match your skills. A private pilot certificate is often called "a license to learn", meaning that you should constantly be learning and polishing your skills as an aviator, and as you work on those skills that you are weak on and push yourself everyone now and then, you will find an adjustment in your personal minimums are necessary. Crosswind landings are a good example, as a person gets more and more proficient at crosswind landings, they will feel more and more comfortable in situations where the crosswind is stronger, and as they get more proficient they will adjust this minimum accordingly.
A few weekends ago, I pushed some of my personal minimums to the edge. I decided I was wanting to make a trip from Renton, WA (RNT) to McMinnville, OR (MMV). Looking at the weather for the flight it didn’t look like it was going to happen as the clouds were going to be lower than I would like for a trip of that length (wanted the clouds at about 4000′). Instead, I decided I would try a different trip, the first part of the McMinnville trip, which would be to Olympia, WA (OLM) to see the museum they have there.
Leaving Renton the ceilings were about 2500′ and light showers in the area, and forecast to improve later on in the afternoon. This was above my personal minimum of 2000′. Flew to Olympia at 1900′ and went through a light rain shower about 5-6 miles north of the airport. We landed and went through the museum there, and walked to get some lunch. Walking back to the airport I didn’t really like the looks of the clouds, as it didn’t look like it had improved much. As we walked out to the airplane, I told my passenger, "hold on a second, I want to do a check of the weather before we leave." Ceiling at Olympia had dropped to 2100′, and it was forecast to be 2500′. 😦 It was about 10 minutes before the next observation, as I told my passenger, "Let’s wait and see what the next observation is…", and it dropped to 1900′. 😦 Looking at conditions along the route, we ceilings would go up as we went north, it was just a matter of getting out of Olympia. After about 30 minutes of pouring over weather reports, forecasts, and aeronautical charts, I had come up with a plan and we would make a break for it before things got worse. Elevation of the Olympia airport is roughly 500′. Ceilings are reported as "AGL", or "Above Ground Level", so 1900′ ceiling means the clouds are at 2400′ MSL (Mean Sea Level) which is what the altimeter in the plane tells you, and VFR rules say would have to stay at least 500′ below the clouds, so 1900′ would be our max altitude leaving Olympia.
Plan was to leave Olympia at "Traffic Pattern Altitude", which is 1500′ MSL, and get to the water as quickly as possible so that if I had to "duck down" I had plenty of room. Would fly to Tacoma Narrows and if it was bad to the north, we would go to the east and up the Kent Valley, and if it was bad in both directions, we would land at Tacoma Narrows and go from there, and if we couldn’t get to Tacoma Narrows, we would turn around and return to Olympia. We got to Tacoma Narrows, and there was a lot of rain to the east, but looked good to the north and west. As we flew up the sound between Vashon Island and the Kitsap Peninsula, I realized that if I couldn’t get to Renton or Boeing Field, Bremerton would be a good "out." We were flying at 1500′ pretty much all the way. We were able to get back to Renton with out a problem, but as we were over Lake Washington and looking south, it wasn’t looking good south of Renton and looked like Renton would be having reain pretty quickly.
Upon landing at Renton I told my passenger, "That is about as marginal as I like to fly…", as the weather was considered "Marginal VFR." I wasn’t scared, but was a bit more nervous about the weather than I normally am. It was a good experience and it showed me, that I can deal with marginal weather. I don’t want to make a habit out of it.
Personal Minimums, along with most things I learned in getting my Private Pilot Certificate, can be applied outside of aviation to one’s personal life and business life. Most people tend to see them as "standards" for themselves in maintaing a good work life balance, maintain good financial health, or improving themselves in either their career or professional life. They are still "Personal Minimums."