Air and water temperature

Lord Paul of Sheffield

Lord Paul of Sheffield

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What effect does the air temperature have on water temperature for fishing?
I'm of the understanding that the water temperature takes longer to change than air temperature, so if there is a spell of cold weather followed by mild weather how long will it take the water temperature to rise?
If there was some reasonably equation it would be good to know when it's likely to be a good day to fish.

Anyone got a rule of thumb

And is there a way of telling the water temperature from knowing the air temperature?
 
barbelboi

barbelboi

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Water temperature changes slower than air temperature because water has a higher heat capacity. Heat capacity is a property of a material that describes how much heat energy is required to change the temperature of a substance by one degree C. About one unit of heat energy is needed to warm the air one degree C. Four times more heat energy is needed to warm the water one degree C.
Jerry
 
S-Kippy

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barbelboi said:
Water temperature changes slower than air temperature because water has a higher heat capacity. Heat capacity is a property of a material that describes how much heat energy is required to change the temperature of a substance by one degree C. About one unit of heat energy is needed to warm the air one degree C. Four times more heat energy is needed to warm the water one degree C.
Jerry
Click to expand...

Bloody Hell Jerry...that's some answer. What was the question again ?
 
Fred Bonney

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Simple formulae, warm water in(rain/run off), cold water warms.

Depends on depth of water and amount of rain how quickly it warms up.

A cold spell, followed by warm South wEsterly rains will warm the water quicker.
 
C

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Fred Bonney said:
Simple formulae, warm water in(rain/run off), cold water warms.

Depends on depth of water and amount of rain how quickly it warms up.

A cold spell, followed by warm South wEsterly rains will warm the water quicker.
Click to expand...

It can be (but seldom is) as simple as "warm water in (rain/run off), cold water warms."

As surely the ground's temp also has a major bearing too, as when warm water (relatively speaking) runs over a cold surface, it reduces the temperature of the run off water.

If you want proof, pour an unchilled drink over a couple ice cubes and take a swig, I bet your drink will be chilled.
 
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The bad one

The bad one

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You haven't said which type of water you are referring to Stills or Rivers?

Here's an answer I gave for rivers elsewhere

Worth noting most rivers, the ones that are entirely fed by ground runoff water correlate within +/- 2 degrees F with the ground temperature within a few days of a settled weather pattern, be that cold or mild.
 
no-one in particular

no-one in particular

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I have a formula but , I am not giving it to a lord and a thread poacher.

All those maids and servants, and living of my taxes, no sense of decency..................
 
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Lord Paul of Sheffield

Lord Paul of Sheffield

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Found this on the net

http://au.answers.yahoo.com/question/index?qid=20070514073517AAqicmM
"Heat energy will always flow from the higher level to the lower. Air does not have the heat capacity of water so it will be quicker to gain or lose it. Thus, the air/water will tend to equalize temperatures as the heat flows from the warm water to the air or warm air to the water. The air's influence over the water temp will be slower than the water's influence over the air".
So if there's a cold spell followed by a warm couple of days it will take longer to warm the water then it will take the water to cool after a warm spell followed by a couple of cool days - that's my understanding of it
 
barbelboi

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Lord Paul of Sheffield said:
So when a lake ices over the water temp keeps constant? - Is this why sometimes breaking the ice on a lake will fish better than a cold lake?
Click to expand...

I think you'll find that when a lake ices over it is a cold lake;) However I've often had good days roach fishing after breaking the ice - I would assume that if the water is frozen they have had time to adjust to the temperature drop (being cold blooded their body temperature will be the same as the water temp. which will obviously be above freezing below the ice) rather than when warmer water lowers in temperature and is about to freeze.
Jerry
 
Lord Paul of Sheffield

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What I was trying to say is that since the temp under the ice will be constant the fish will have become accustomed to it, whereas with a lake that isn't frozen but water temp changing the fish will not feed as well. I know I didn't put it right (and probably still haven't) :D
 
barbelboi

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Apologies for the first sentence Paul - couldn't resist it. I think the rest of the post pretty much agrees with what you think you said...........:D
Jerry
 
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