Answer: Weather is correct.
Explanation:
Weather is a situation of atmospheric pressure during a short span at a particular place.
Climate is a situation of patterns of weather after analysing statistical data during a longer period of a place.
Weather can change in seconds, minutes, hours, days etc.
Whereas climate is the average of changes in weather.
According to question, We were having a picnic, but a thunderstorm was suddenly over us. This was due to a change in weather.
Hence, weather is correct .
