Forecast models can disagree because each model uses different data, resolution and calculation methods.
Rainfall is especially sensitive to small changes in temperature, moisture, terrain and the position of weather systems. Thunderstorms and isolated showers may develop at a different time or place from the forecast.
When models disagree:
Compare the timing and location of rain across all available models.
Check whether a regional model covers your location.
Review Rain Radar and observations for current conditions.
Check the next forecast update.
Allow extra flexibility if the decision is weather-sensitive.
Model disagreement is useful information: it shows that there is more uncertainty in the forecast.