Training 7 ball and 5 club juggling requires me to look up into the sky for durations of up to one minute. Frequently, this is very taxing on my eyes and, frustratingly, requires me to wear sunglasses.

Certain atmospheric conditions are much easier on my eyes. In these conditions, the sky is a very deep blue and I can train juggling without sunglasses, even during mid-day. Atmospheric conditions that have good visibility for juggling almost always cause airplanes to leave extremely long contrails.

The Appleman chart shows that contrails form at relatively low temperatures, low relative humidity, and high pressures. Are predictions of these temperatures and pressures available? This information would be helpful in scheduling my juggling training sessions.

  • $\begingroup$ Just a note: The linked question features the Appleman chart which has been created for low-bypass-engines. Refer to the new chart by Jeffrey L. Peters for high-bypass-engines. You can find the document here. The chart is on document page 16, respectively PDF page 22. $\endgroup$ Jul 18 '18 at 15:10

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