I live in Western Washington State, a bit north of Seattle.
Typical hay season is a fairly damp spring, followed with a dry summer and periodic showers in the fall. Haying in the spring, to get the first cutting is challenging, with moisture content being high. However, this first cutting sets up a good quality second cutting in June/July with good weather conditions.
Spring haying, you have to take advantage of every break of the weather to hopefully bring in the hay. Getting it off the ground is paramont as there is so much moisture in the ground. With the excess moisture in the spring, bales are heavier, and are more like bricks.