We where about to sleep in the woods and decided who takes what 2 hour shift as lookout. The DM was new to D&D but knowledgeable about tabletop games and asked us a simple yet stupefying question: "How do you know when 2 hours passed?"

My immediate reaction was "an hourglass".
Another player said we'd have a candles that burn more or less one hour each. Another said: candle + sun dial.
Another said: we use the sky/stars (weather dependent though).

I could not find an answer for the 3.5 setting and I can find flaws with all of these solutions. Is there a super easy way we can't think of?


4 Answers 4


All of your suggestions are good answers. In 3.5 specifically, the use of skills like Survival and Knowledge(Local) seems appropriate to accurately gauging time, as does casting a spell at CL 2 that lasts 1 hour per level (like Mage Armor). Your suggestions are actually better in most cases, though.

Hourglasses in 3.5 are 25 gp and weigh 1 pound. (or free and weightless. Thanks to HeyICanChan for noting the 1st level Sorc/Wizard spell slow burn, which requires an oil-filled hourglass as a material component with no listed cost. Assuming these keep decent time, they are the obvious choice)

That's neither heavy nor expensive, and easily portable.

Using the stars and other environmental conditions sounds like a survival check to me, and makes sense (adding a sundial is kinda dumb unless there's a moon out and you have low-light vision, and even then you should call it a moon dial so I am less annoyed by the idea of you using a sundial to track time at night :P) It's obviously less accurate than other methods, but it's free and honestly most of the time no one cares if your party sleeps for 9 hours 45 minutes or 10 hours 15 minutes. Precision just isn't that important when it comes to your watch shifts, and, honestly, all really precise watch shifts do is make it easier for an enemy to coordinate an attack on your camp at night.

Using 1-hr candles is basically the same as an hourglass except it produces light and needs to be kept out of the rain and wind and such, which makes it usable is slightly fewer circumstances (generally, you're using this while camping, which means you already want to be out of the wind and rain and away from possible hostile Spot checks, which is usually possible even in bad environments due to things like Rope Trick and Mordenkainen's Magnificent Mansion). 1-hr Candles cost just 1 cp, so an hourglass takes 1,250 watch shifts to break even. Candles also are weightless, which can be nice.

I suppose, given the question, I should note the water clock in the PHB, which is the wrong way to keep time-- expensive, bulky, and sensitive to motion.

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    \$\begingroup\$ I think the "precision just isn't that important when it comes to watch shifts" part could be more prominent. \$\endgroup\$
    – Erik
    Commented Oct 17, 2017 at 18:42
  • \$\begingroup\$ @Erik Eh, I think I'd rather give the OP the benefit of the doubt and assume there is some reason why precise timing matters in this case (co-ordinated assault on separate targets in the morning, predawn, with a separate group or something like that). When I move it to the top of the answer rather than where it is I feel like it ends up coming across as a bit berate-y, akin to Dale's answer. It's an important point, but it's tangential to the question unless the asker didn't yet think of that. If you have a suggestion on how to make it prominent, though, without that, please do! (or edit) \$\endgroup\$ Commented Oct 17, 2017 at 23:07

You are making a false assumption ...

You are thinking an “hour” is 3600 seconds - this has only been the case since clocks and watches became widespread in the 19th century.

In the medieval period that D&D is usually set in an “hour” is approximately 1/12th of the time between dawn and dusk or 1/12 of the time between dusk and dawn. Except on the equinoxes night time and day time hours are different lengths. Only, not even then are they the same length because dawn and dusk depend as much on topography as time of year (days are longer on mountains than in valleys) and the whole thing is subjective anyway.

Ocean going ships were more rigorous in their timekeeping because it was how they navigated but for everyone else an hour had passed when you felt an hour had passed.

Before clocks and artificial light people worked when it was light, slept when they were tired and ate when they were hungry. There is strong evidence from 17th and 18th century diaries that, particularly in the winter, people would go to bed when the sun went down, wake sometime in the night and chat, eat, have sex etc and then go back to sleep until the sun came up.

A person on watch would wake the next person when they felt they’d done their bit and so it would go until the sun came up.

While this is all very interesting I can’t actually see why it matters from a gameplay perspective - if you decide there are four watches a night and something interesting happens, roll a d4 and it happens on that watch.


Wake the next person up:

  • When that piece of wood in the campfire has burned through.

  • When that incense stick has burnt to the bottom.

  • When you have walked the camp perimeter twenty times.

  • When the crude water clock (a container with a small hole allowing water to exit slowly) is empty.

Now, none of these are exact or precise, but who cares? In a camp in the wilderness it doesn't matter if you are on watch for 2:00 hours or 2:10 or 1:50. Even if an exact timekeeping device is present (which might not be possible depending on tech/magic level), exact timekeeping is not needed. All we need is something accurate enough to make sure all the party spend roughly the same time on watch.

  • \$\begingroup\$ This could use a bit more explanatory context for why these things, which aren't precisely 2 hour measurements per the question, form an answer to the question anyway. I personally see what you're implying, but it's more helpful to not leave that as an exercise for the reader. \$\endgroup\$ Commented Oct 18, 2017 at 1:17
  • 1
    \$\begingroup\$ In my experience taking watches there's an internal ~water~ clock that fills slowly and tells you when a couple of hours have gone by.... \$\endgroup\$
    – nitsua60
    Commented Oct 18, 2017 at 1:23
  • \$\begingroup\$ Wood is unpredictable, material, size, weight is in question. Also, you'd have to carry them since you wouldn't find what you want just laying around in the forest. \$\endgroup\$
    – Discipol
    Commented Oct 18, 2017 at 19:02
  • \$\begingroup\$ Incense stick sounds good, minimal light and could be odorless to not attract unwanted attention via smell checks :D \$\endgroup\$
    – Discipol
    Commented Oct 18, 2017 at 19:03
  • \$\begingroup\$ Walking makes noise, motion and requires energy. Although if an ambush would come, a moving target is harder to hit than a still one. \$\endgroup\$
    – Discipol
    Commented Oct 18, 2017 at 19:04

Historically speaking, it was common to keep time by singing.

Popular songs were known to take a certain amount of time to play / sing. When silence and/or stealth was needed, the songs could be mouthed or recited mentally.

For example, the original version of Greensleeves was known to take about half an hour to play all the way through, if I recall correctly.

Make the bard earn their keep, for once. ;D

  • 1
    \$\begingroup\$ Hudson Hawk approves \$\endgroup\$
    – Adeptus
    Commented Oct 20, 2017 at 2:12
  • \$\begingroup\$ Platinum, baby. ^^ \$\endgroup\$
    – nijineko
    Commented Oct 20, 2017 at 15:08
  • \$\begingroup\$ That's quite an interesting piece of information! \$\endgroup\$
    – Discipol
    Commented Oct 23, 2017 at 13:19

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