Netherlands does the same thing. training races start in february and the real racing starts in march. Consequently, people burnout by the time summer comes around most years. there are races all the way into september but the huge turnouts are in the spring and then it declines from there, going from 100+ riders down to 25 or so in september per category.
Generally, people are roaring to start racing because they have been training all winter. Then it turns out that these races in **** weather and lots of wind are hard. They don't get the results and slowly the motivation wanes throughout the season.