During the past three weeks I've been grafting pecan trees almost every day. I've grafted trees at the Pecan Experiment Field, during grafting schools, and on my own farm. The weather forecast for this coming week is cloudy, wet, and cool--great grafting weather. At every break in the rain, I'll be outside grafting even more trees.
One of the most frequent questions I receive during grafting schools is--"How long can I keep grafting?" The answer, like almost every outdoor activity, is that it depends on the weather. The grafting season ends when daytime high temperatures start to climb into the low 90's F. High heat seems to literally cook newly placed grafts to death. In the past, hot weather occurred as early as mid-May in SE Kansas. Most years, the heat will hold off until June.
I watch the long range forecasts to see when weather experts predict the first real heat wave. If a week of mild temperatures is forecast before the heat hits, I'll keep on grafting. If a heat wave is immenant, making additional grafts is not a good idea.