Guidance on average overnight temperatures

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Stormflex
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Location: Basingstoke, Hampshire

Guidance on average overnight temperatures

Post by Stormflex » Thu Jan 26, 2012 5:23 pm

Hi,

I'm totally new to bivvying/bikepacking, having simply done a couple of bivvys on foot towards the end of last summer. I'm planning on getting out more this year, both on bike and foot and am currently researching sleeping bags - what a headache! Whilst weight and packsize is clearly going to be important to me, I'm a little uncertain on what temperature rating I should be looking for.

If I take a look at the Met Office forecast for Basingstoke for the next few nights it shows Fri, Sat and Mon 1c and Sun down to 0c. This gives me a reasonable indication of what I might need if I was to go out this weekend say. But, thinking ahead into the spring and summer...

For example, if I bought a MHW Lamina 20 with a 1c comfort rating, which might be great for now, I'm guessing in the summer months I'd be cooked alive!

Any thoughts on average overnight temperatures during the summer in lowland locations, for example Hampshire?

Thanks.

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Bearbonesnorm
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Re: Guidance on average overnight temperatures

Post by Bearbonesnorm » Thu Jan 26, 2012 6:05 pm

Bit of a can of worms this one ;)

Do you sleep hot or cold ? It's surprising what a difference it'll make.

IMO it's worth getting a bag which is rated for colder temps than you think you'll encounter, you can always unzip it a touch if you get too hot. Away from built up areas it's not that uncommon to have a light frost at anytime of the year. Here's some of what I used at various times last year.

Go-lite Adrenaline 1 - Comfort rating of +4. From the end of May until Sep it was fine when used with a good mat and a light down jacket.

Detuer 550 - Comfort rating of 0, used when the temps have hovered just above freezing. Again, when used with a good mat and jacket I was warm enough. If the temp dropped below 0 you found out quite quickly.

If you're not planning on using it in winter conditions then I'd look for something with a comfort rating of at least 0 and add or remove clothing as required. Like I said though, I sleep cold, so other will have a different opinion. ;)
#corporate shill for hire

didnothingfatal
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Re: Guidance on average overnight temperatures

Post by didnothingfatal » Thu Jan 26, 2012 7:37 pm

I'd get one which covers the worst you expect, and then if too warm open the zip and stick a limb out.

griffdowg
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Re: Guidance on average overnight temperatures

Post by griffdowg » Thu Jan 26, 2012 9:41 pm

Worth noting what the numbers actually mean,

Check what the ratings comply to. hopefully EN13537

The standard measures four temperature ratings:

Upper Limit — the temperature at which a standard man can sleep without excessive perspiration. It is established with the hood and zippers open and with the arms outside of the bag.

Comfort — the temperature at which a standard woman can expect to sleep comfortably in a relaxed position.

Lower Limit — the temperature at which a standard man can sleep for eight hours in a curled position without waking.

Extreme — the minimum temperature at which a standard woman can remain for six hours without risk of death from hypothermia (though frostbite is still possible).

standard man is assumed to be 25 years old, with a height of 1.73 m and a weight of 73 kg; a "standard woman" is assumed to be 25 years old, with a height of 1.60 m and a weight of 60 kg.

So depending on age (Stu is obviously old because he sleeps cold :lol: ) this may guide you a little better.

For me, the lower limit does not seem that bad. 8 hours, without waking? thats my usual night at home. I would quite happily go with this a dozen nights a year. For me my cover all bag is a Lamina 35 which is comfort 5, limit 1 This does me right through spring/summer/autumn. for anything colder I turn to my mountain equipment Starlight 3 or titan 850. I always use a liner, in colder temps a sea to summit reactor which adds a degree or 2 if used correctly.

Listen to what Stu says, insulation from the ground and correct use of a bag is key. Depending on what other clothing you have you may get more versatility out of a lighter bag/down jacket set-up.

So to conclude, I would go for a comfort of around 3-5 degrees with coresponding lower limit of -3 to 1 degree.

any help?

G

ps. the outdoorshop.com have a good bag sale on at the mo. RAB ascents are fairly cheap for what they are as are some of their synthetics.

PPS, I assumed your a man in my suggestions! women sleep colder (like Stu) ;)

Anthony
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Re: Guidance on average overnight temperatures

Post by Anthony » Thu Jan 26, 2012 10:41 pm

You'll be lucky really to find a bag that suits you for use all year round.

I would look at something that goes down to about 2-4'C (3-400g of high quality down for example) for 3 season use, then either look at buying a specific winter bag (min -5/10ish) or an insulated jacket/mat to boost the other bag.

Stormflex
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Location: Basingstoke, Hampshire

Re: Guidance on average overnight temperatures

Post by Stormflex » Fri Jan 27, 2012 12:50 pm

Thanks folks for your responses.

Apologies, I had meant to address the whole "do you sleep hot/cold?" thing in my original post but forgot. I'd say I tend to sleep on the hot side. Also, I should probably have mentioned that I invested in a POE Peak Elite AC last year, after having a really terrible nights sleep on a closed cell foam mat.

To date I have been looking at synthetic bags with a comfort around the 3/4/5c and plan really on sleeping out from say April to September. Then I started wondering if I was actually looking at the right temperature rating for what I wanted to do.

The MHW Lamina 35 (5c) has been fairly high on my list for it's lightweight, small pack size and cost. I've also been looking at bags like the Vango Ultralite 300 (4c) and ME Starlight II (3c). The Vango packs down nice and small as well and can be had for £45 (and is tested to EN 13537:2002).

The only down clothing I own is a Rab Microlight vest, perhaps this in conjunction with a decent polartec fleece would do me for colder nights.

Accept that I'd need to buy a seperate winter bag if I wanted to sleep out ealier/later in the year.

Any thoughts on the Vango bag? It's a bit of a bargain at pretty much half the price of the Lamina.

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gairym
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Re: Guidance on average overnight temperatures

Post by gairym » Fri Jan 27, 2012 1:25 pm

i just invested in a Vango Venom 300 which i found online (i can post the link if interested) for £69 (rrp £117).

here's a link to the spec:

http://www.vango.co.uk/sleeping-bags/venom-300.html

i used it for the first time last night at roughly 2 degrees (with an Alpkit Hunka XL Bivi bag and on a cheap foam mat) and it was toasty warm (wearing just biking tights and a merino base-layer)!

also.....would you recommend the POE Peak Elite AC mat???

each time i use my cheap foam mat i am really pleased by how cheap and light it is (and it insulates ok too) but am increasingly pissed-off by how uncomfortable it is and i think it's time to invest in something a little better.

cheers, gairy.

EDIT:

has anyone used the Thermarest Z Lite mat???

(http://cascadedesigns.com/en/therm-a-re ... te/product)

i've never used one but on paper it looks good (especially when the price is factored in).

opinions....?

p.s. sorry for slight highjack of thread but it's all on-topic - hope you don't mind.

didnothingfatal
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Re: Guidance on average overnight temperatures

Post by didnothingfatal » Fri Jan 27, 2012 2:02 pm

The POE Elite AC is a really nice mat, It's light and with a better R rating than the NeoAir. The only mat I have that I have that is warmer is a Exped Down Mattress. Also have that Thermarest Z lite, it's light and functional but the volume is too much, I normally fit a pair to the base of my mountain tent to stop ground chill a little when camping for extended periods. If you want closed cell type mat, The OMM Duo mat is a good system and doubles up as a decent pad in your pack.

Stormflex
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Location: Basingstoke, Hampshire

Re: Guidance on average overnight temperatures

Post by Stormflex » Fri Jan 27, 2012 2:08 pm

Hi gairy,

Thanks for the thoughts on the Venom - I have looked at it as well. I'm more drawn to synthetic for it's ease of use/care but haven't totally discounted down.

I have only slept on the Peak Elite AC twice but have found it a considerable improvement over a closed cell foam mat, in terms of comfort if nothing else. I sleep on my side and found that, with the foam mat, I slept for no longer than an hour at a time before I woke with an aching hip. At that point I'd turn on to the other side and repeat the process!

I found the POE mat really comfortable, easy to inflate/deflate, packs down to next-to-nothing and given the vertical tube design does a good job of keeping you on the actual mat - it cradles you and stops you rolling off.

That said, I've just Googled the mat to find some reviews for you and note there is discussion about faulty mats leaking, which worries me! I must admit, despite blowing it up fully, my mat was certainly softer in the morning but not completely flat. I put this down to a bit of valve leakage and my weight on it!

See http://markswalkingblog.wordpress.com/2 ... eping-mat/

Might be sticking mine in the bath later!

Anthony
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Re: Guidance on average overnight temperatures

Post by Anthony » Fri Jan 27, 2012 3:55 pm

As the air temperature drops, a decrease in mat pressure is perfectly normal and to be expected. If you can feel the ground through it however then yes, you may have a leak!

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royAB
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Re: Guidance on average overnight temperatures

Post by royAB » Fri Jan 27, 2012 6:22 pm

Thanks for that observation Anthony - 'thought' that was what was happening to mine (couldn't find a leak) but good to have it confirmed..

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gairym
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Location: Chamonix, France (but a Yorkshire lad).

Re: Guidance on average overnight temperatures

Post by gairym » Fri Jan 27, 2012 7:07 pm

didnothingfatal/Stormflex,

thanks - it's looking like a good option.

has anyone seen/used these:

http://kookabay.com/luxlite.html

not so good on the insulation front but possibly good for comfort???

Stormflex
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Joined: Wed Nov 02, 2011 2:09 pm
Location: Basingstoke, Hampshire

Re: Guidance on average overnight temperatures

Post by Stormflex » Fri Jan 27, 2012 9:19 pm

Anthony, thanks for the reassurance. I wasn't aware of the reported problems before today but, as I say, mine never ended up flat.

MM-on-POINT
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Re: Guidance on average overnight temperatures

Post by MM-on-POINT » Sat Jan 28, 2012 2:55 am

I have a mhw lamina 20 and find it pretty warm for spring to autum but I am also a hot sleeper I wouldn't use this for any think below 5c and have felt cold in it around October! as the other guys have said make sure you have a decent mat what ever bag you get.

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