Rock Climbing in Rocky Mountain National Park in mid-May?

How is the weather in mid-May?

Usually afternoon t-storms - be down by Noon.

Higher up in the park, it may be snowing mid May. Most precip above 11,000 feet will likely be snow. There may be fresh snow and things could be wet. Then again, it could be sunny and 60 degrees. If you are looking at north-facing climbs such as those on Hallett's, don't expect them to be warm, dry rock climbs.

Lumpy should be good, though.

Check out the CMS Conditions Report for climbing conditions in the RMNP.

Some of the south facing routes (Petit, Saber, etc) may be nice and dry at that time of year, but you may have a little (or more than a little depending on the spring snow season this year) snow to contend with on the approach. North facing routes like Halletts, Sharkstooth, etc will most certainly be too cold and wet. There are some decent late season alpine snow/ice climbs that sometimes are in good condition at that time of year (Dragon Tail, Dreamweaver, Ptarmigan Fingers). Climbing at the Flatirons, or Eldo should be perfect. Lumpy can be a bit chilly in the morning, but very nice in the afternoon.