Question

The Sun Has Long Been Set
by William Wordsworth
The sun has long been set,
The stars are out by twos and threes,
The little birds are piping yet
Among the bushes and trees;
There's a cuckoo, and one or two thrushes,
And a far-off wind that rushes,
And a sound of water that gushes,
And the cuckoo's sovereign cry
Fills all the hollow of the sky.
Who would "go parading"
In London, "and masquerading,"
On such a night of June
With that beautiful soft half-moon,
And all these innocent blisses?
On such a night as this is!

What time of year is this poet describing?