You don't have to be a weatherman to know which way the wind blows...

The weather is so erratic, it rains in one town, yet is sunny in another - Long Island no longer has the same daily weather

When I coached I tried to wait as late as possible but it always came down to safety first.
I recall early on after I got my hand-me-down Chevy Impala convertible (aka The Tank) that it was nasty as all hell in Floral Park (and Bellerose -- essentially same nabe but different zips and names) but beautiful at Jones Beach. Often I can recall rain at Shea (or Citifield) and nary a drop here or vice-versa.
Rain has not stopped the concerts outdoors; it delayed the Go Gos but the show was worth it. Last year, perhaps the best show of the summer - Squeeze at Coney I. (with The Romantics opening -- had a rather smaller crowd because of the weather (My wife and a couple known to all canceled out because of the rain -- email if you need the set list!)
Some of the best concerts back in the day at Wollman Rink in Central Park featured rain as much as great music.
The biggest difference today concerns my pool club where -- under the latest "management" they pull all stops to open and do not let morning sprinkles justify closing or not opening (for which past executive directors bragged saved the facility money as staff did not beed to get paid)

I digress, when I rec'd an email at 4pm yesterday that 3 hours of cheerleading practice was canceled due to bad weather, I wanted to do back flips myself. Then to see the sun shining I did not know what to do---unexpected free time is rare.