A Vague Span
から〜にかけて marks a stretch of time or space with fuzzy edges.
- 夕方から夜にかけて雨が降るでしょう。(Rain is expected from evening through the night.)
Against から〜まで
The pair to keep apart, and the difference is precision:
| Pattern | Edges |
|---|---|
| から〜まで | exact — a defined start and end |
| から〜にかけて | approximate — the span as a whole |
九時から五時まで is office hours. ×九時から五時にかけて sounds wrong for a precise schedule — clock times are exact, and にかけて wants vagueness.
What Goes In It
Broad periods and regions: 春から夏にかけて, 関東から東北にかけて, 昨夜から今朝にかけて.
You will meet it constantly in weather forecasts, which is the single best place to hear it used naturally.
The Event Spreads Across the Span
Whatever happens is spread over the whole period, not concentrated at one point. That is why it suits rain, road works and gradual change rather than a single event.