A large number of similar things that happen in a short time, like a spate of rainy days.
A spate can make people think of too much of something, like too much rain or too many bad things happening.
Examples:
There was a spate of bad news this week.
A spate of new books came out at the library.
The spate of sunny days made everyone happy.
I had a spate of good luck last month.
There was a spate of snow that covered the whole town.
The spate of new toys made the kids very happy.