from the park website:
The best conditions for climbing are from March through May and September through early November. Climbing in the summer can be extremely hot, especially on unshaded walls.
Due to the nature of sandstone, climbing is not recommended for inexperienced climbers. The climbs here are high, exposed, big wall climbs. Because of Zion’s 2,000 foot cliffs few areas are suitable for top roping.
There are no sport climbing opportunities in Zion.
Sandstone is weak when wet. Avoid climbing in damp areas or after rain. Afternoon thunderstorms are common in July and August. Thin wafer-like holds should not be trusted. Brush the sand off the rock before attempting delicate friction moves.
----------------------
Bouldering
There are two accessible bouldering areas in the main canyon. One is 40 yards west of the south entrance. This is a house sized boulder that poses a variety of options and problems. The other site is .5 mile north of the south entrance. Drilled Pocket Boulder is located on the west side of the road and is a slab with an obvious south facing crack.
----------------------
Permits
Permits are not required for day climbs but are required for all overnight bivouacs.
----------------------
Route Closures
Some rock formations and routes are closed to climbing from March 1 to mid-July each year to protect nesting peregrine falcons. Some areas that are routinely closed include the Great White Throne, Cable Mountain, Court of the Patriarchs, and the Streaked Wall. Check below or at Visitor Centers for current closures.
Current Cliff Closures
Check often: list of closed cliffs updated regularly
The areas listed below will be closed starting March 1, 2011.
Climbers are responsible for checking the specific maps of the closure areas. [see website for maps]
•Angels Landing
•Mount Isaac
•Mount Kinesava
•Middle Fork of Taylor Creek
•Tunnel West
•Mountain of the Sun and North Twin Brother reopened on April 27, 2011.
•East Temple, Mount Spry and Streaked Wall reopened on April 26, 2011.
•The Great White Throne and Cable Mountain reopened April 19, 2011.
----------------------
Route Descriptions
Desert Rock by Eric Bjornstad, and Rock Climbing Utah by Stewart Green, are published climbing guides for Utah and the Colorado Plateau. They include routes in Zion National Park as does Zion Climb; Free and Clean by Bryan Byrd.
Informal notebooks of route descriptions have traditionally been kept by climbers at the backcountry permits desk at the Zion Canyon Visitor Center. Climbers are welcome to look at these books at the permits office.
Climbers should realize that because descriptions in all guides are volunteered by climbers of varying abilities, there may be inaccuracies. Do not rely completely on route descriptions.
The National Park Service neither endorses nor confirms the accuracy of the information. You assume all risks and are responsible for your own safety. If you complete a new climb or wish to make changes or additions to current descriptions you may add to these notebooks.
----------------------
Minimum Impact Climbing
•When approaching a climb use established trails to prevent further erosion of slopes.
•It is illegal to camp at the base of the wall or in your vehicle.
•White chalk causes undesirable visual impacts; add red pigment if chalk is used.
•Tube or bag human waste and carry it out. Do not drop your waste.
•Remove all old, worn rope and equipment.
•Gardening, the pulling of vegetation from cracks, is prohibited.
•Do not remove fixed pins.
•Make sure your climb is adequately protected by visually inspecting any preexisting bolts or fixed pins.
•It is illegal to use a power drill to place bolts.
•Never climb directly above trails where hikers may be hit by dislodged rocks.
(
visit link)