2027 eclipse weather strategy: climate now, forecast later
The biggest planning mistake is treating long-range climatology like a forecast. Use different weather information at different stages of the trip.
Months ahead: use climatology to choose the region
Long-range climate is useful for comparing broad tendencies, not predicting one morning in 2027. A dry August climate can justify choosing one region over another, but it cannot promise a cloud-free eclipse.
Two weeks out: begin tracking forecast consistency
At this stage, look for large-scale patterns and model agreement rather than a single cloud-percentage number. The exact cloud deck at one field is still too uncertain for a final move.
Three days out: switch from destination planning to positioning
Now the practical question becomes: which reachable place inside totality has the best combination of cloud forecast, road access and horizon? This is when Plan B and Plan C become operational.
Eclipse morning: protect optionality
Do not move simply because one model shows a tiny improvement. Consider traffic, road closures, heat and how easily you can return. A clear-sky forecast is only valuable if you can reach the location safely and remain inside totality.