Clothing and Temperature
Clothing levels are matched to different levels of extreme temperature, as given in the table below:
Effects of Heavy Clothing: Encumbrance is given in stone units. The number shown under “Dex” is a penalty to all Dexterity-based rolls (including missile attacks and AC); the raw Dexterity score is effectively reduced by 3 times the number shown in the table. Clothing gives comfort in the temperature bands shown. Chain cannot be worn with clo 4, plate neither clo 3-4. The given clothing types are the best possible without magical construction.
Modifiers to Temperature: Ranges for comfortable temperatures assume a moderate work load (e.g., marching). Sedentary persons will require +1 clo, while heavy labor needs –1 clo (e.g., running or fighting). If persons are not adequately clothed, then they must seek shelter to resolve the condition. Assume that garments are removed for comfort when needed. Standard mounts can work acceptably in temperature ranges clo 0-2.
Lack of Proper Clothing: Living creatures suffer 1d6 damage at the end of each hour that they are outside their comfort range by one step. Additional steps accrue damage more quickly: Every 10 minutes for 2 steps, minute for 3 steps, and round for 4 steps. This damage cannot be healed until shelter is reached, at which point they regain 1 hp/level for each like time period. If under half hit points for this reason, then assume the creature’s movement is halved.
High Temperatures: Hot weather categories are not shown on the table, but they may be continued in like fashion: Hot (90-120° F), Very Hot (120-150°), and Extremely Hot (150-180°). These are not suitable for working or travel, and even at clo 0 creatures take damage as per the rule above unless sedentary or in shelter.
Notes and References
- “Clo” is a standard unit of clothing thermal insulation, where one clo gives comfort for a sedentary person in a normal office environment (70° F). Technically, 1 clo = 0.88 R (R is ft²·°F·hr/Btu) = 0.155 K·m²·W⁻¹. Individual garments are often expressed in decimal clo and summed for total effect. Here we massively simplify to integer values only. See: https://en.wikipedia.org/wiki/Clothing_insulation
- Costs approximated from the Medieval Sourcebook: Medieval Prices (cloth and clothing), with the scaling of shillings × 3.
- Temperature levels and side effects are the International Labour Office, Encyclopedia of Occupational Health and Safety, Ch. 42: Heat and Cold. See especially Figures 42.22 and 42.14. We might also consider applying clothing check penalties to search and surprise (“Distraction... Impaired vision”), but for simplicity this was not included. See: http://www.ilocis.org/documents/chpt42e.htm
- Armor may be more wearable with heavy clothing/cold weather than is expressed here, but the rule here is considered conservative, playable, and challenging. See personal recollection here: http://www.mmo-champion.com/threads/2149761-Knight-armor-in-cold-weather?p=44136592&viewfull=1#post44136592
- Values of work output and other data (esp. Appendix C and D): http://www.blowtex-educair.it/downloads/thermal%20comfort.htm
- Times of hypothermia onset (see slide 14): https://www.slideshare.net/openmichigan/2012-gemcreshollimanhypothermoer
- Expected survival time in cold water with flotation device is around 2.5 hours: http://seagrant.umn.edu/coastal_communities/hypothermia
- High-temperature ranges of “Warm” match NOAA “Caution” category; “Hot” is “Extreme Caution” to “Danger”; “Very Hot” is as “Extreme Danger”: http://www.nws.noaa.gov/om/heat/heat_index.shtml, http://www.weather.gov/ama/heatindex
Having extra clothing for a winter environment is pretty critical. I've gone overnighting in -15 ot -30 with windbreak shelter and found it's best to take off outer travel layer and put 2 fresh layers on. I also remove my inner most socks to make sure no sweat stays near feet and put on camp shoes. But that sort of thing is picky real life stuff.
ReplyDeleteVery true!
DeleteOk... You gave an explanation for using feet, stones, etc.
ReplyDeleteWhy use Fahrenheit?
And why plate is worst than chain in cold weather?
DeleteWell, I think in-game we'd just use a descriptor like "Warm", "Cool", etc. -- or the Clo rating itself. Of course, at some point we have to express the relation to modern units (like 1 stone = 14 pounds) so people can do conversions for the game when necessary (see post two weeks back). Possibly it's the use of Clo in game that's really criticizable. Do you know of another temperature scale that could be used (even more archaic than Fahrenheit)?
DeleteThe idea of the plate restriction was that it doesn't fit with the bulky clothes necessary -- and frostbite could occur from touching frozen metal parts. I'd be very open to changing that if there was evidence to the contrary.
According to the Wikipedia article "Timeline of temperature and pressure measurement technology", you won't do much better than Fahrenheit or Celsius. It looks like the first temperature scale (along with the word "thermometer" itself) wasn't devised until 1624. The Fahrenheit and Celsius scales were only about 100 years later, and all of them are well past the medieval period, so it's anachronistic no matter which one you choose.
DeleteI see claims that the earliest quantitative measurement of temperature was with the "Galileo Thermometer" circa 1603, but can't find what units were used (link).
DeleteDaniel & were looking at the same article simultaneously. :-)
DeleteThanks for the response, guys!
DeleteOk. Whatever the temperature unit I would overlap the ranges a bit to incorporate that feeling that different people use different clothings and you can use both clothings when temperatures is near the limiar. Something like you always see that guy using shorts even when it is snowing. In game, I think there will always some DM who will say "It is cool (clo 1) but the sun is shining so its near warm (clo 0)"
Based in the fact that plate limits the amount of clothing and chain is full of holes, I think both could limit protection from clo 3-4.
The idea is that you can wear chain more easily than plate with heavy clothing because the chain is flexible and doesn't need to be fitted precisely to the contours of your body like plate does - hence being usable at one higher clo rating than the plate.
DeleteAs an youngish (35) UK person I have no good feel for Fahrenheit, only Celsius, so providing both would be really handy.
DeleteAlso when it comes to human weight, stone is very familiar, but I struggle with just pounds, usually taking out my calculator (maths PhD, simple arithmetic is beyond me!). Anything else (other than human height) and I can only work in metric.
spaceLem: That's a good point -- I just updated the table and a column for Celsius. (Approximate conversion for a simple number; bands are 15 deg wide instead of proper 16⅔.) Thanks for the suggestion!
DeleteThanks for that, I'm looking forward to seeing the final result!
DeleteIf you don't mind losing the regularity, you could improve the accuracy a touch by widening the Clo 2 band to [-20, 0] (knocking everything from -15 to -45 down by 5).
Looks good,
ReplyDeleteI assume there is a implied 90* - 120*/ 120+ range for "comfort/damage" for hot climates?
maybe a couple asterisks on clo3/4 to draw attention to the armor rule?
You are correct about the hot weather implication! Good idea about maybe highlighting the table that way.
DeleteHot climates probably demand some additional granularity and/or modifiers - a brutally humid 80 to 90 degrees Fahrenheit (think Florida in the summer) is as bad or worse than 110 degrees of dry heat, as long as you're properly watered anyway. Of course, sandy deserts (and if the average temperature is above 90 degrees, you're probably in one) present additional problems, such as sandstorms and the relentless sun bearing down on you, problems that actually make it desirable to have a fully-covering set of linen or cotton clothing.
DeleteI would say the above rules combined with the Food and Water rules from last week would account for the differences bettwen dry and humid heat well enough.
DeleteI can attest from personal experience that there is a difference between "wet" cold and a "dry" cold as well :)
Places in hot climates also gives you "Apparent temperature" along with "Actual temperature" which is exactly what you want: "It is 90°F but but because of humidity and such, it is 110°F apparently".
DeleteI don't think you need more granularity. Just keep it to DM judge which weather level is: "Ok. You are in Amazon forest, it is over 100°F and so humid that mizzles. It is hot as f** level... clo -1"
G.B. Veras:
DeleteThat was exactly the situation I had in mind - that in the Amazon rain forest, it actually rarely goes above 90 degrees, so a strict reading of these rules would put an 80 degree rain forest in the same category as a pleasant 65 degree spring day in New England.
I live in the opposite side of Brazil (Southern, near Uruguay and Argentine) but I know it is usually around 90°F there and can go up to 110°F in record days. In truth, the summer down here is so wet that can have a variation of 15°F between apparent and actual temperature.
DeleteBack to the rules... Just consider the column "Temp" as "Apparent temperature" instead of "Actual temperature".
I just added a paragraph on High Temperature to make that explicit. I kept the same granularity, and assume that you're measuring total effective Heat Index for that assessment.
DeleteAwesome work, Delta! :D
DeleteMulling this over some more, I want to build on what G. B. Veras said before about possibly having some overlap; I'd go even further and say that one should be allowed to go somewhat outside the ideal clo-to-temperature range without suffering damage - or at least not in the short term, maybe have some kind of grace period, or add a category where damage accrues more slowly than 1d6 per hour. At least on the high temperature side of things, the rule seems too strict... it might be fine as-is for the cold. I'm just thinking of say, marathon runners at the summer Olympics (warm to hot, clo 0, running), farmers harvesting crops in late summer (warm to hot, clo 1, moderate work), or the like. Even old-timey Georgia chain gangs (warm to hot, clo 0, hard work), while very bad for the long-term health and well-being of the prisoners, didn't have people dropping dead after two hours.
DeleteAs Daniel says, it's a good point that for realistic work the damage levels are pretty harsh. I could add the identical caveat as for food/water; we could delay damage for 1 or 2 time units.
DeleteI'm very torn about that, but for now I've settled on this rule for (1) simplicity, and (2) balancing gameplay for mid-level PCs in the wilderness.
Well of course use it as you see fit, but if I use something like this I think what I'll end up doing is using a one-category radius "discomfort" zone. So if you're doing moderate work in normal clothes in warm weather, you'll be sweaty and uncomfortable but not taking any damage. It also works well in the other direction, making it relatively safe down to 30 degrees - I like this since doing a moderate amount of work like marching, jogging, etc. should be enough to stave off hypothermia, and of course frostbite isn't possible at all unless the temperature is low enough to freeze water.
DeleteCome to think of it, I might use your table as-is in cases where characters are out in the rain, humidity is extremely high, or they're otherwise exposed to a lot of water - since water both exacerbates body temperature loss in the cold and prevents sweating in the heat, I think the strictness/harshness of the table would be very realistic if applied to characters who are, for one reason or another, soaked.
DeleteThis also leads to some interesting questions when you factor in non-humans. Would dwarves be able to withstand colder climates without bundling up so much? Would elves due to their connection to the wilds and their magically imbued cloaks and boots be able to ignore the weather? Would orcs or goblins negligent of the cold or heat due to their unnatural toughness? I have a vague sense that dogs, for example, don't experience hypothermia the same way humans do. I also know that larger animals have an easier time maintaining body temp than smaller ones, so giants and ogres can probably withstand cold weather that would kill a human or even worse a halfling.
ReplyDeleteI would just shift the table up or down a level for animals truly adapted to colder/warmer climates. I choose shift because usually when you adapt to cold, you make yourself vulnerable to warm. So I would keep hill giants as is but shift the values for frost and fire giants, for example.
DeleteExceptional work as usual, Delta!
ReplyDeleteI would like to think about a ruling on the effects of wrapping oneself in a heavy cloak or winter blanket (which started being a common entry on the equipment lists in later editions).
Thanks! A heavier outer layer ought to increase the clo rating appropriately.
DeleteHonestly, in the literature I find that people are just summing clo ratings of various garments for a total figure. I'm not sure that extrapolates to the extremes we see here, however. I kind of didn't want people to just buy 4 gambesons and think they're fine at any temperature.
That works. On reflection, I might say that the winter blanket is the thing that adds an extra clo when you're sedentary, but otherwise isn't practical.
DeleteI would probably allow desert-specialized robes/tunics that permit travel in dry Hot conditions.
I could see the utility in having a winter cloak available on the equipment list. Perhaps "+1 to wearer's CLO, with associated penalties, takes 1 round to remove before combat."
DeleteWhat a delightful series.
ReplyDeleteRegarding armour vs. cold, I have a friend who does historical re-enactments and he experiences a very narrow temperature band for which chain mail is comfortable (14-21 C IIRC). Not sure what he is wearing underneath; I will ask.
If true, then there are two effects:
- chain (and plate) may be off the table for even lower temperature categories
- for high(er) temperatures, these may be off-limits as well
That is great stuff to know! Thanks so much. If you do get extra information from your friend, I would to hear about it.
DeleteLate comment, but I'm looking at a Dragon #15 article on OD&D weather by David Tillery. I can't help but notice he has a special temperature category called "Fair" for "A beautiful day. There are no checks for diseases, and any party has moral of +2, and fights with a +1." This inhabits the almost exact same narrow band piles talked about above (60-70 F).
DeleteTook some time, but I have some more info.
ReplyDeleteHe experiences that the optimal temperature with or without (metal) armor is virtually the same. In his case that is 14 degrees C when performing light activities, such as walking around.
The main difference is that an increase or decrease in temperature wrt the optimal temperature, is perceived more strongly with armor.
Thus he is overheated more easily when temperature is above 14 degrees and undercooled below 14 degrees, in case he is wearing (metal) armor.
In case of chain mail with linen clothing underneath (or other thin garments), the optimal temperature is said 14 degrees, and the experienced temperature is something like 14 + 2*dT (dT = actual temp - 14).
This means that there is hardly any measure against overheating; it will become too hot already slightly above 20 degrees C.
He never wore any wooly clothing beneath his chain mail, and he expects that the comfortable temperature will drop accordingly, but that the impact of the delta wrt this optimal temperature will stay large. Thus, the range of comfort will always be narrow, regardless of your choice of isolating material.
That said, he expects that the temperature of comfort with woolen underclothing will be higher when wearing (metal) armor than without armor, since metal conducts heat so well, shifting the equilibrium temperature upwards wrt the situation without this armor.
No numbers here; he does not have the experience with woolen garments.
Hope this helps!
That is an amazingly fantastic observation! Thank you immensely for asking about that and sharing!
Delete