Water Temperatures

[Wildswimmer Pete]

Would it be of interest if I reported water temps whenever I go swimming outdoors - which I do all year round? Of course anybody else would be welcome to make their contributions.

I regularly check my thermometer's calibration at 0C and it's always within 1C.

Wildswimmer Pete

[chriscw]

Would be very interesting especially if you recorded them in the more widely used Fahrenheit system.

[Wildswimmer Pete]

Would be very interesting especially if you recorded them in the more widely used Fahrenheit system.

Yes - I can give them in both units with F rounded to nearest 0.5 degree. First one from yesterday:

River Biam, Aylestone Meadows, Leicester, 6-8-10: 17C, 63F

Wildswimmer Pete

[TheKrikkitWars]

Would be very interesting especially if you recorded them in the more widely used Fahrenheit system.

Forgive my ignorance, but isn't Celsius/Centigrade the standard UK unit for temperature and has been since well before I was born?

[Wildswimmer Pete]

Forgive my ignorance, but isn't Celsius/Centigrade the standard UK unit for temperature and has been since well before I was born?

It was back in 1963 (I was a 13yo tadpole) when the first attempts were made to persuade the British public to adopt Celsius and it's only comparatively recently, around the last 10-15 years, that Fahrenheit has been dropped completely from weather forecasts. The US sticks resolutely to Fahrenheit except for scientific work.

As I have a scientific background I think in both Celsius and Fahrenheit, the latter for the weather.

Wildswimmer Pete

[Wildswimmer Pete]

River Weaver, Frodsham Marsh, Cheshire, 7-8-10: 21C (70F)

About right for the time of year. This is my local (and usual) swimming spot about half a mile upstream from the put-in under the M56 viaduct.

Wildswimmer Pete

[Mission]

.

As I have a scientific background I think in both Celsius and Fahrenheit, the latter for the weather.

what about poor mr kelvin? :p

[Wildswimmer Pete]

.

As I have a scientific background I think in both Celsius and Fahrenheit, the latter for the weather.

what about poor mr kelvin? :p

Well he's Celsius plus approx. 273 but a bit cumbersome for everyday use. Really I was just pointing out that like many of my generation we had to use both scales until Celsius became widely accepted. In my early working life (late 1960s) I did laboratory work which meant that I had to "learn" to use Celsius at a time when the public at large still thought very much in Fahrenheit.

Wildswimmer Pete

[SimonMW]

ell he's Celsius plus approx. 273 but a bit cumbersome for everyday use.

He's also mainly used for measuring colour temperature for video and film, which I suppose could be quite a novelty way of indicating what the weather will be like! Although unfortunately it could confuse people because bluer is warmer.

[TheKrikkitWars]

.

As I have a scientific background I think in both Celsius and Fahrenheit, the latter for the weather.

what about poor mr kelvin? :p

If you're thinking like that I'm sure Mr Rankine would be unhappy at sliding into the abyss of progress too.

[GrahamC]

This would be very useful Pete. Today we paddled up the Weaver from Winsford Flash to as far above the measuring weir that we could manage and we were commenting on how much warmer the Flash water was than the river itself. I have not thought of monitoring water temperatures but I think that this could be of value.

Graham

[Wildswimmer Pete]

Today we paddled up the Weaver from Winsford Flash to as far above the measuring weir that we could manage and we were commenting on how much warmer the Flash water was than the river itself.
Graham

Bear in mind that Winsford Flash is very shallow so warms up quickly. I did a sponsored swim down it in the summer of 1986 and was dragging my belly on the bottom (seriously) until I found the channel that wends its way through it. I don't think they've dredged it since.

Hatchmere (lake), Delamere Forest, Cheshire, 8-8-10: 20C (68F, 293K)

Wildswimmer Pete

[Wildswimmer Pete]

River Weaver, Frodsham, 9-8-10: 21C (70F)

Wildswimmer Pete

[GrahamC]

Wow, I am really surprised that the water is so warm. This makes a bit of sense as my kids have been spending lots of time in Brereton lake and always say that it is warmer in the water than outside when I tell them to get back in the kayaks/canoes.

Pete, I think I read that you swim in winter too, do you deliberately acclimatise to colder water or simple let the seasons do it for you. I am very wary of the dangers of cold water immersion (taking a k1 out alone at night in the winter) would wild swimming improve my chances?

Graham

[Wildswimmer Pete]

Pete, I think I read that you swim in winter too, do you deliberately acclimatise to colder water or simple let the seasons do it for you. I am very wary of the dangers of cold water immersion (taking a k1 out alone at night in the winter) would wild swimming improve my chances?

Graham

Yes - I do swim outdoors in just cozzie through the winter. However you need to be cold-acclimatised to swim in water at single-digit temperatures and this isn't psychological but involves major physiological changes such as regeneration of brown fat, suppressed cold-shock response, increased metabolic rate when immersed, altered blood chemistry, modified circulation and the development of a thick layer of subcutaneous fat to mention a few. Conditioning takes a long time (two winters in my case), is regarded to be irreversible, and involves gradual lengthening of immersion time in increasingly cold water.

Normal wild swimming in "sane" water temperatures (15C +) won't result in the physiological adaptation needed for the hardcore cold-water game. Winter swimming is a recognised extreme sport.

Oddly enough if I fell out of a boat in winter into icy water I'd have problems. It takes full bare-skin immersion to trigger my cold response and this wouldn't happen if I were clothed. Even a cold shower won't do the trick.

Wildswimmer Pete

[Wildswimmer Pete]

River Weaver, Frodsham, 10-8-10: 21C (70F)

Wildswimmer Pete

[Wildswimmer Pete]

River Weaver, Frodsham, 14-8-10: 20.5C (approx 69F)

Down a little but there was a stiff current suggesting quite a bit of rain in the catchment. Meanwhile I know it's not inland but briny, but I had a swim in the sea at Pwllheli on Thursday 12th, water temp was 18C (64F) which is a bit on the low side. That part of Cardigan Bay usually reaches 20C (68F) in a decent summer.

Wildswimmer Pete

[Wildswimmer Pete]

Hatchmere (lake), Delamere, Cheshire, 15-8-10: 20.5C (69F)

Wildswimmer Pete

[Wildswimmer Pete]

River Weaver, Frodsham, Cheshire, 16-8-10: 20C (68F)

Definite cooling trend.

Wildswimmer Pete

[Wildswimmer Pete]

River Weaver, Frodsham, 22-8-10: 22C (72F)
Ditto today, 25-8-10: 20C (68F)

Wildswimer Pete

[Wildswimmer Pete]

River Weaver, Frodsham, 27-8-10: 19C (66F)

Definite cooling trend now.

Wildswimmer Pete

[Wildswimmer Pete]

Hatchmere, Delamere Forest, Cheshire: 29-8-10: 18.5C (65F)

A bit on the low side for the end of August - I'd expect 20-21C after a "normal" summer.

Wildswimmer Pete

[Wildswimmer Pete]

River Weaver, Frodsham, 30-8-10: 17.5C (63.5F)

That's down nearly 5C in seven days - not good.

Wildswimmer Pete

[Owen]

[
River Biam, Aylestone Meadows, Leicester, 6-8-10: 17C, 63F

Wildswimmer Pete

You've got me there, I grew up very near to Aylestone Meadows. I know the Soar and Sence as well as the Grand Union Canal (I learnt to swim in this) but I've not heard of the Biam. Where is it?

[peakfreak]

River Weaver, Frodsham, 30-8-10: 17.5C (63.5F)

That's down nearly 5C in seven days - not good.

Wildswimmer Pete

Hi Pete

I have been watching this thread with interest, I take it from your "Not Good" comment that it is not normal for temperatures to drop approx .5 degree per day? What would be classed as normal drop over time? Or is it just a finger in the air calculation over time, much like some of the weather people on the TV seem to go by :-)

[Wildswimmer Pete]

You've got me there, I grew up very near to Aylestone Meadows. I know the Soar and Sence as well as the Grand Union Canal (I learnt to swim in this) but I've not heard of the Biam. Where is it?

It's a small river that's also a tributary of the Soar, and it runs along the Soar's floodplain.

Wildswimmer Pete

[Wildswimmer Pete]

Hi Pete

I have been watching this thread with interest, I take it from your "Not Good" comment that it is not normal for temperatures to drop approx .5 degree per day? What would be classed as normal drop over time? Or is it just a finger in the air calculation over time, much like some of the weather people on the TV seem to go by :-)

The temperature of large water bodies reacts slowly to changes in ambient temperature and is a good indicator of long-term tends. Such a rapid drop has two causes:
a.) A large amount of cold rain dumped in the catchment
b.) Radiative and evaporative cooling during cold nights
and would normally happen towards the end of September or during early October.

Last week's weather was appalling for August by anybody's measure and Thursday became very close to becoming the coldest summer day on record with a maximum of just 11C recorded in Buxton. We are now experiencing unseasonally cold nights with widespread ground frosts - pretty unusual for August. I am sticking my finger in the wind and it's getting bloody cold! Winter 2010 lasted for some six months, spring never arrived, and for most of us summer was three weeks in June. Much of July and all of August was more of a very early autumn and the sudden chill of the last few days, more characteristic of the end of September, is causing me to have a bit of a bad gut feeling about the coming winter. Early and cold?

On the other hand 2010's weather shows distinct similarities to that of 1963 when the worst winter of the 20th century was followed by a cold spring (it snowed on my 13th birthday, 21st April). There were two short hot spells - one in mid-May and one in June. The rest of the summer was utter crap, but the bad weather cleared at the end of August to give fine warm days with chilly nights. Autumn '63 ended up as an extended Indian summer with the only cold snap of an otherwise nondescript winter during the couple of weeks leading up to Christmas.

So is it going to be a repeat of '63's "golden autumn" or the run down to an early, long and very cold winter? I just don't know.

Wildswimmer Pete

[matt_outandabout]

Right, that's it, I am measuring Loch Tay tomorrow...all this water temps in teens and up is just too good to be true ;-)

[peakfreak]

...We are now experiencing unseasonally cold nights with widespread ground frosts - pretty unusual for August. I am sticking my finger in the wind and it's getting bloody cold! ...

I'm glad you said that Pete, I said to my wife and the neighbours last night that the past couple of evenings were considerably colder than normal and to expect a cold winter this year. They looked at me as if I was mad (which normally I am).

[Wildswimmer Pete]

River weaver, Frodsham, 31-8-10: 20C (68F)

Seems I might have been a little too pessimistic as the Weaver has recovered nicely despite last night being unseasonally cold. Yesterday's low temp could well have been due to a "slug" of cold water from Thursday's cold rain. What will also help is that the next few nights aren't expected to be as chilly as recently.

Wildswimmer Pete