Option 1: Stormy weather- This option indicates a sudden fall in barometer reading. A storm is characterized by strong winds, heavy rain or snow, and dark clouds. These factors create a rapid drop in barometric pressure, which is measured by a barometer. A sudden fall in the barometer reading is often associated with the approach of a low-pressure system, which typically brings unsettled weather conditions.

Option 2: Calm weather- Calm weather is characterized by light winds and clear skies. It is unlikely to indicate a sudden fall in barometer reading as there is no significant change in weather conditions.

Option 3: Cold and dry weather- Cold and dry weather refers to low temperatures and low humidity levels. While this type of weather can be associated with high-pressure systems, it does not necessarily indicate a sudden fall in barometer reading.

Option 4: Hot and sunny weather- Hot and sunny weather is often associated with high-pressure systems and stable atmospheric conditions. It is less likely to indicate a sudden fall in barometer reading.

In conclusion, option 1 (stormy weather) is the correct answer as it is typically associated with a sudden fall in barometer reading due to the approaching low-pressure system.