Spell.
A collective noun for dry weather is spell. eg. A spell of dry weather
Dry wit, dry weather, and dry wine.
dry sunny weather
drought can last but the simple dry weather wont
There is no standard collective noun for 'dry weather', however, the term sometimes used is a spell of dry weather.
the weather is dry rainy hot
the weather in Nubia is hot and dry
the weather is dry rainy hot
hot dry weather
A time of dry weather with little rainfall is called a drought.
clear, dry weather
weather = simple subject dry = simple predicate