Just got back from 7 great days of climbing at Red Rocks, warm in the sun, and though it was a little cool in the shade it was fine if you wore a fleece and carried gloves for early morning shady belays. We thought the weather was actually great (expecially for the longer hikes in) and kept the crowds away.
We did several moderate trad climbs - Tunnel vision (5.6), which was fun, though the tunnel pitch is a bit weird and hard to protect. Crimson Chrysalis (5.8) was a terrific climb, 9 pitches and the top pitches are the best, so make sure you get there early (fairly steep approach hike). Dark Shadows was very enjoyable too. After doing all of these shady climbs and desperate for a day in the sun we did Beulah's Book, a great 5.9- with a really interesting bombay chimney move as the crux. Not as hard as it looks but spooky. We could have continued on Solar Slab but several parties ahead of us (who had ascended other routes on the lower section) convinced us we didn't have time.
If you want to do the longer routes, get an early entry/late departure pass (free) from the rangers at the BLM visitor center. They give you the pass code for the gates so you can come in as early as 5am to start your approach and leave as late as 8pm without the $50 ticket.
We found that if we hit the gates right as 7 when they opened we were the first climbers out. . .not too many early risers, even on the weekend. The pullouts got crowded by around 10 on the weekends, though.
Make sure to go have beers at Bonnie Springs resort around the open fire while you are out there. . . (it's just past the old Oak Creek Campground off 159).
Have a great time. I wish I were still there!