The short answer to that is yes - but the real answer is it depends.

If you are climbing on sandstone, this could actually be very dangerous & unethical. The issue with sandstone is that it tends to be a fairly porous rock. After heavy rains, it is likely to have absorbed some quantity of water in those pores. This weakens the rock, compared to the very same rock with empty pores. Depending on conditions (ambiant humidity levels and rock itself), it may take some time before it is safe to climb again. The issues about climbing on wet (porous) sandstone is that it is much more likely to break off if you fall on your pro (not necessarily a huge chunk falling down, but you only need the surface to chip out to take out your cam/nuts...) and also that you could break holds. That's bad for safety AND for climbing ethics.

Red rocks (near Las Vegas) recommand here 24 hours after rain before climbing - I've heard people talking about 36 hours there to be safe too: Las Vegas Climbing Concil

However, Red River Gorge (Kentucky) is also largely sandstone though of a much stronger type. I've been climbing often there while it rained, mostly in the roofy areas where the rocks tends to stay dry, although it will begin to seep in the cracks if it rains enough. I also climbed there in the spring - with all the snow melting, even if the surface of the rock is dry, the cracks are often seeping so it is safe to assume there's moisture in the rock. It's mostly sport climbing though, but the point about the rock being liable to break is just as valid. Bolted routes at Red Rocks are

  just as discouraged after rains as trad climbs.

If you do a long route, and get caught in the rain, you may then have to climb on wet rock anyways. Of course there's a difference between taking a risk because elements force you to and walking to the crag voluntarily to take that same risk (wet rock). But to show it is not an absolute no-go, depending on rocks.

The main thing is that wet rock will bite less into your placements than dry one, generally speaking. So each placement should be considered with more caution - raise your standards as to what you will consider a good one. Chokes will tend to be less affected than cams because the friction doesn't matter as much - but be aware that it is more likely it will move after you go so be extra careful for this (perhaps equalize more than you otherwise would have).

Regarding freezing, I am aware of nothing that would make much of a difference between say 20 Celsius wet rock a 2C rock. If you mean below freezing, then I would point out that mix climbing (rock & ice) do use both ice screws & rock protections for their ascents (though these guys are crazy, IMO). One of the issue that I see with this however is that it may be more difficult to determine is the rock is fractured (because it may not ring as hollow if ice fills the cracks).

Regarding manufacturer's inputs:

Metollius seems to think so:

Metollius about wet/icy rocks

My opinion on this however (regarding manufacturer's input) is that they are all likely to say it is riskier just because of liability. They are unlikely to provide useful guidelines as to how much riskier or when it is safe regardless. E.g. to me the fact that they describe it as riskier doesn't mean it's a no-go - all things being equal, trad climbing is riskier than top-rope....

The short answer to that is yes - but the real answer is it depends.

If you are climbing on sandstone, this could actually be very dangerous & unethical. The issue with sandstone is that it tends to be a fairly porous rock. After heavy rains, it is likely to have absorbed some quantity of water in those pores. This weakens the rock, compared to the very same rock with empty pores. Depending on conditions (ambient humidity levels and rock itself), it may take some time before it is safe to climb again. The issues about climbing on wet (porous) sandstone is that it is much more likely to break off if you fall on your pro (not necessarily a huge chunk falling down, but you only need the surface to chip out to take out your cam/nuts...) and also that you could break holds. That's bad for safety AND for climbing ethics.

Red rocks (near Las Vegas) recommend 24 hours after rain before climbing - I've heard people talking about 36 hours there to be safe too: Las Vegas Climbing Council

However, Red River Gorge (Kentucky) is also largely sandstone though of a much stronger type. I've been climbing often there while it rained, mostly in the roofy areas where the rocks tends to stay dry, although it will begin to seep in the cracks if it rains enough. I also climbed there in the spring - with all the snow melting, even if the surface of the rock is dry, the cracks are often seeping so it is safe to assume there's moisture in the rock. It's mostly sport climbing though, but the point about the rock being liable to break is just as valid. Bolted routes at Red Rocks are just as discouraged after rains as trad climbs.

If you do a long route, and get caught in the rain, you may then have to climb on wet rock anyways. Of course there's a difference between taking a risk because elements force you to and walking to the crag voluntarily to take that same risk (wet rock). But to show it is not an absolute no-go, depending on rocks.

The main thing is that wet rock will bite less into your placements than dry one, generally speaking. So each placement should be considered with more caution - raise your standards as to what you will consider a good one. Chokes will tend to be less affected than cams because the friction doesn't matter as much - but be aware that it is more likely it will move after you go so be extra careful for this (perhaps equalize more than you otherwise would have).

Regarding freezing, I am aware of nothing that would make much of a difference between say 20 Celsius wet rock a 2C rock. If you mean below freezing, then I would point out that mix climbing (rock & ice) do use both ice screws & rock protections for their ascents (though these guys are crazy, IMO). One of the issue that I see with this however is that it may be more difficult to determine is the rock is fractured (because it may not ring as hollow if ice fills the cracks).

Regarding manufacturer's inputs:

Metollius seems to think so:

Metollius about wet/icy rocks

My opinion on this however (regarding manufacturer's input) is that they are all likely to say it is riskier just because of liability. They are unlikely to provide useful guidelines as to how much riskier or when it is safe regardless. E.g. to me the fact that they describe it as riskier doesn't mean it's a no-go - all things being equal, trad climbing is riskier than top-rope....

The answer to that is it depends.

If you are climbing on sandstone, this could actually be very dangerous & unethical. The issue with sandstone is that it tends to be a fairly porous rock. After heavy rains, it is likely to have absorbed some quantity of water in those pores. This weakens the rock, compared to the very same rock with empty pores. Depending on conditions (ambiant humidity levels and rock itself), it may take some time before it is safe to climb again. The issues about climbing on wet (porous) sandstone is that it is much more likely to break off if you fall on your pro (not necessarily a huge chunk falling down, but you only need the surface to chip out to take out your cam/nuts...) and also that you could break holds. That's bad for safety AND for climbing ethics.

Red rocks (near Las Vegas) recommand here 24 hours after rain before climbing - I've heard people talking about 36 hours there to be safe too: Las Vegas Climbing Concil

However, Red River Gorge (Kentucky) is also largely sandstone though of a much stronger type. I've been climbing often there while it rained, mostly in the roofy areas where the rocks tends to stay dry, although it will begin to seep in the cracks if it rains enough. I also climbed there in the spring - with all the snow melting, even if the surface of the rock is dry, the cracks are often seeping so it is safe to assume there's moisture in the rock. It's mostly sport climbing though, but the point about the rock being liable to break is just as valid. Bolted routes at Red Rocks are

just as discouraged after rains as trad climbs.

If you do a long route, and get caught in the rain, you may then have to climb on wet rock anyways. Of course there's a difference between taking a risk because elements force you to and walking to the crag voluntarily to take that same risk (wet rock). But to show it is not an absolute no-go, depending on rocks.

The main thing is that wet rock will bite less into your placements than dry one, generally speaking. So each placement should be considered with more caution - raise your standards as to what you will consider a good one. Chokes will tend to be less affected than cams because the friction doesn't matter as much - but be aware that it is more likely it will move after you go so be extra careful for this (perhaps equalize more than you otherwise would have).

Regarding freezing, I am aware of nothing that would make much of a difference between say 20 Celsius wet rock a 2C rock. If you mean below freezing, then I would point out that mix climbing (rock & ice) do use both ice screws & rock protections for their ascents (though these guys are crazy, IMO). One of the issue that I see with this however is that it may be more difficult to determine is the rock is fractured (because it may not ring as hollow if ice fills the cracks).

Regarding manufacturer's inputs:

Metollius seems to think so:

Metollius about wet/icy rocks

My opinion on this however (regarding manufacturer's input) is that they are all likely to say it is riskier just because of liability. They are unlikely to provide useful guidelines as to how much riskier or when it is safe regardless. E.g. to me the fact that they describe it as riskier doesn't mean it's a no-go - all things being equal, trad climbing is riskier than top-rope....

The short answer to that is yes - but the real answer is it depends.

If you are climbing on sandstone, this could actually be very dangerous & unethical. The issue with sandstone is that it tends to be a fairly porous rock. After heavy rains, it is likely to have absorbed some quantity of water in those pores. This weakens the rock, compared to the very same rock with empty pores. Depending on conditions (ambiant humidity levels and rock itself), it may take some time before it is safe to climb again. The issues about climbing on wet (porous) sandstone is that it is much more likely to break off if you fall on your pro (not necessarily a huge chunk falling down, but you only need the surface to chip out to take out your cam/nuts...) and also that you could break holds. That's bad for safety AND for climbing ethics.

Red rocks (near Las Vegas) recommand here 24 hours after rain before climbing - I've heard people talking about 36 hours there to be safe too: Las Vegas Climbing Concil

However, Red River Gorge (Kentucky) is also largely sandstone though of a much stronger type. I've been climbing often there while it rained, mostly in the roofy areas where the rocks tends to stay dry, although it will begin to seep in the cracks if it rains enough. I also climbed there in the spring - with all the snow melting, even if the surface of the rock is dry, the cracks are often seeping so it is safe to assume there's moisture in the rock. It's mostly sport climbing though, but the point about the rock being liable to break is just as valid. Bolted routes at Red Rocks are

just as discouraged after rains as trad climbs.

If you do a long route, and get caught in the rain, you may then have to climb on wet rock anyways. Of course there's a difference between taking a risk because elements force you to and walking to the crag voluntarily to take that same risk (wet rock). But to show it is not an absolute no-go, depending on rocks.

The main thing is that wet rock will bite less into your placements than dry one, generally speaking. So each placement should be considered with more caution - raise your standards as to what you will consider a good one. Chokes will tend to be less affected than cams because the friction doesn't matter as much - but be aware that it is more likely it will move after you go so be extra careful for this (perhaps equalize more than you otherwise would have).

Regarding freezing, I am aware of nothing that would make much of a difference between say 20 Celsius wet rock a 2C rock. If you mean below freezing, then I would point out that mix climbing (rock & ice) do use both ice screws & rock protections for their ascents (though these guys are crazy, IMO). One of the issue that I see with this however is that it may be more difficult to determine is the rock is fractured (because it may not ring as hollow if ice fills the cracks).

Regarding manufacturer's inputs:

Metollius seems to think so:

Metollius about wet/icy rocks

My opinion on this however (regarding manufacturer's input) is that they are all likely to say it is riskier just because of liability. They are unlikely to provide useful guidelines as to how much riskier or when it is safe regardless. E.g. to me the fact that they describe it as riskier doesn't mean it's a no-go - all things being equal, trad climbing is riskier than top-rope....