That sounds 'a bit brisk' to me.
(Of wind or the weather) cold but pleasantly invigorating:
- A cold, brisk wind fills the square on a grey Saturday afternoon.
- Though the wind was brisk and chilly, the sun was bright and warm.
- The September night was chilly, with a brisk wind picking up, but neither seemed to notice.
Here in the UK it's often (though not always) used as a form of humorous understatement, for example on the coldest day of the year you might say "oooh, it's a bit brisk out, isn't it?" c.f. "Nice weather for ducks!"
If it's less cold than you expected then it's mild. As in, "we had a mild winter".
(Of weather) moderately warm, especially less cold than expected:
Tropical continental air is very dry and tends to bring very warm weather during the summer and unseasonably mild weather during the winter.
Plants suffer most when warm / mild weather is suddenly replaced with cold.
October has come round again and the weather is still mild, with the cold snap we had last weekend coming as a shock.
Example usage: https://www.flickr.com/photos/heandfi/4141559844/