are there lots of summer activities at lake arrowhead

Check out these family-friendly reviews of several activities in Lake Arrowhead: http://www.trekaroo.com/places/lake-arrowhead-california/activities

Also note that there is a great Lake Arrowhead Village with shops, restaurants, and a nearby playground.

Because Lake Arrowhead is a private lake owned by the homeowners of Arrowhead Woods, the only access to the lake is by being a property owner, or a guest of one. The only public options are the Arrowhead Queen Boat Tour, waterskiing through the McKenzie Water Ski School, or strolling the boardwalk at Lake Arrowhead Village. (see reviews on Trekaroo for these activities). There is public access to nearby Lake Gregory which has a County Park with swimming, boating, fishing, and a giant water slide.

I don't know whether the water is cold in June or not... but I'm guessing that it is much warmer than a snow melt river, but much colder than a heated swimming pool!

We love going to Lake Arrowhead to visit the Village. There is a playground, ducks and fish to feed, shops and restaurants, a small amusement area with carousel & mini-golf, go carts, etc... It is a fun family day trip. Eat at the Belgian waffle works! (review coming soon!!)