A timely snow promises a good harvest. This idiom conveys the idea that a beneficial snowfall, occurring at the right time, is a sign of a productive agricultural season ahead. Here's an analysis of the key components:1. "Timely" indicates that the snowfall is occurring at an appropriate or opportune moment, suggesting it will benefit the crops rather than hinder them.2. "Snow" refers to the precipitation, which in this context, is not harmful but rather contributes positively to the farming process.3. "Promises" suggests that there is an expectation or likelihood of a positive outcome, specifically a good harvest.In essence, the phrase reassures that the current weather conditions, with the appropriate snowfall, are predictive of a successful crop yield. It is a traditional belief that a deep snowpack during the winter can provide moisture for the soil during the growing season, leading to better crop development and ultimately, a higher harvest.