So you had a plan. Then the gophers showed up. Or the mercury hit 70 in February.
Sticking to a rigid plan with gardening can be dangerous. Historical data is informative but should never drown out what we see and hear in a garden. Looking for cues from plants is the best way to proceed with gardening tasks.
Make it rain. Or turn on your irrigation system for half a day to simulate a rainstorm. Antsy to start your frost tender plants now? What will you do if there's a cold snap in April?
Gardening is one of the few professions where experts often try to eliminate change [see hedges in Webster]. Course-correcting nature requires constant adjustments because nature constantly changes.
Improvising will produce its share of comedic moments. Hopefully some unexpected and beautiful ones as well.