$twcweather Observations

[WCmore]

Quote from @Koyfam:

$twcweather.alerts Observations

Couple more additions that I didn’t see in the Wiki.

$twcweather.forecast.daypart[0].wxPhraseLong - Mostly Clear/Wind, Few Showers

(expression) $twcweather.forecast.daypart[0].wxPhraseShort - Clear, M Clr/Wind, Few Showers, AM Showers

I’m working on the latest data now…

[WCmore]

The Wiki has been updated.

Thanks @dejavux2 and @Koyfam!!

[julio8a]

Hello,

looking for some help here, not sure what i’m doing wrong.

When I add this ($twcweather.forecast.daypart[0].narrative) to my expression, it returns the entire array.

When I add this ($twcweather.forecast.daypart[1].narrative) or any other number inside [#] it doesn’t return anything.

Same happens when I use:

$twcweather.forecast.daypart[0].uvIndex
$twcweather.forecast.daypart[0].daypartName

I’m a total newbie with this weather data and using it in webcore.

[WCmore]

For the next 48 hours, try:

$twcweather.forecast.daypart[0].narrative[0]   (Today AM)
$twcweather.forecast.daypart[0].narrative[1]   (Today PM)
$twcweather.forecast.daypart[0].narrative[2]   (Tomorrow AM)
$twcweather.forecast.daypart[0].narrative[3]   (Tomorrow PM)

Just keep in mind that half of the time, [0] will be null… (from approx 3pm to 3am)

---

Same goes with:

$twcweather.forecast.daypart[0].uvIndex[0]
$twcweather.forecast.daypart[0].uvIndex[1]
$twcweather.forecast.daypart[0].daypartName[0]
$twcweather.forecast.daypart[0].daypartName[1]
etc

[julio8a]

Thank you!

Make sense now, I was missing targeting the array values at the end with [#]

[WCmore]

Trying to find the chance of rain TODAY… only getting multiple days with…
{$twcweather.forecast.daypart[0].precipChance}
how can I extrapolate just today’s percentage?

Here you go:

$twcweather.forecast.daypart[0].precipChance[0] = Today AM
$twcweather.forecast.daypart[0].precipChance[1] = Today PM
$twcweather.forecast.daypart[0].precipChance[2] = Tomorrow AM
$twcweather.forecast.daypart[0].precipChance[3] = Tomorrow PM
etc...

Just keep in mind that the one ending in [0] will be “null” half of the time.
(approx 3pm to 3am)

[WCmore]

That’s fantastic @WCmore.

Is there a way in an expression we can get the medium of

$twcweather.forecast.daypart[0].precipChance[0]
and
$twcweather.forecast.daypart[0].precipChance[1]
?

As is the case now [0] is null
and [1] is 40, so we’d have 40.

but tommorow if [0] is 40 and [1] s 50 we’d get 45. it would be neat to always get a figure to work with…

You can find the average by using:
( [0] + [1] ) / 2

… but you will need extra code ahead of that to determine if [0] is “null”… and if so, to just use [1] as the “average”.

[WCmore]

Awesome, like … round(sum($twcweather.forecast.daypart[0].precipChance[0], $twcweather.forecast.daypart[0].precipChance[1], ), 2)

I’ll monitor over next few days, thank you Sir.

One observation though…

If you have an AM with 0 percent chance of rain, and an evening chance of 90%, then your daily “average” will be very misleading at 45%.

[WCmore]

You forgot to divide your sum by two…

---

Also, I have only seen even numbers, so rounding the average is likely not necessary…
(unless you decide to round more than two dataPoints)

[WCmore]

I think I need some help!

{$twcweather.forecast.daypart[0].precipChance[0] + $twcweather.forecast.daypart[0].precipChance[1]} / 2

is giving me 20, when [0] is null and [1] is 40.

So is this giving me 20

round(sum{$twcweather.forecast.daypart[0].precipChance[0] + $twcweather.forecast.daypart[0].precipChance[1]} / 2)

I’m looking for the average figure and if one figure is null value then ignore it, dont think this can be done without a lot of math.

Yes, you would need to add a step before that line of code…

Something like:

IF [0] is "null"
    Then use [1]
    Else use ( [0] + [1] ) / 2
END IF

[WCmore]

Pretty confident this should do it…
All this just to delete the official Weather Station tile!

I think you have a bit of strange syntax in your last post, as well as missing data for the “round” command.

If you want to round the answer to a whole number, here is the expression I would use:

round((sum($twcweather.forecast.daypart[0].precipChance[0],$twcweather.forecast.daypart[0].precipChance[1]) / 2),0)

---

Changes I made:

• Expressions do not need curly brackets
• Sum needs parenthesis, not curly brackets
• Sum needs a comma, not a “+”
• Round needs to know how many decimals places to round to

[WCmore]

One other “food-for-thought”…

After 3pm, when [0] returns null… It is important to remember that the [0] forecast is literally done and over with.

For example, at 4pm, the data from earlier that morning [0] should not really be a factor at all for the rain you can be expecting that afternoon.

Just my two cents.

---

What I do in my home is to try to determine the rain chance for the next 8 hours. (since I am rarely outside longer than that). This is kind of tough though, since TWC only shows 12 hour increments. My current method is something like this:

From  4am to  8am, use [0]              (AM data thru 3pm)
From  8am to  3pm, use ([0] + [1]) / 2  (today's AM/PM average)
From  4pm to 11pm, use [1]              (PM data thru 3am)
From 11pm to  3am, use ([1] + [2]) / 2  (PM today + AM tomorrow average)

Just keep in mind that any execution that happen in the 3 o’clock hour may go either way.
(the update time varies quite a bit, as seen here)

---

Edit 2022:

I have created a piston to outsmart this craziness…
(to make sure that the same query always returns the current data)

[stone]

Just as a suggestion, it might be nice to include a short paragraph at the top of the Wiki page that explains how to set up and use the $twcweather variables.

I am just getting started with weather so here are my suggestions from someone experiencing this with new eyes.

After searching for a couple of hours, I haven’t really figured out how to set up this feature and configure the specific weather station. Perhaps a brief overview of the steps to set it up, configure the weather station, and then an example piston that does something like turn on a light when the current temperature rises above a certain value.

Also, it might be nice to describe in the Wiki how often the data is updated, and whether or not you can change the interval.

Hope that this helps!

- Brad

[WCmore]

Thanks for the feedback. If I may address these one by one:

it might be nice to include a short paragraph at the top of the Wiki page that explains how to set up and use the $twcweather variables.

Variables can keep track of anything, so are not limited to $twcweather.
(IE: The weather page is not the place to learn about variables)

---

I haven’t really figured out how to set up this feature and configure the specific weather station. Perhaps a brief overview of the steps to set it up, configure the weather station

There is nothing to setup. (other than telling SmartThings your location)
The data is always available, but it is up to us to make the query efficiently.

---

an example piston that does something like turn on a light when the current temperature rises above a certain value

Here is one that checks every half hour.

---

it might be nice to describe in the Wiki how often the data is updated

There has not been any public information released, so the $twcweather Wiki contains our own personal observations. I suspect the update time is very different in different locations (since weather providers are different worldwide)

---

whether or not you can change the interval.

I doubt this is possible yet. I mean, you can change how frequently you make the query, but that does not mean that anything new came in yet.

Typically, I make my weather queries once per hour. Temps every 30 min. Alerts every 15 minutes.

Try to not go overboard though please, because SmartThings is billed for each and every query. We don’t want to abuse it, because they will start charging us for this data.

[WCmore]

On another topic

Thanks for your speedy reply to my forum post. It points out that I am probably making this harder than it needs to be.

When I try to duplicate the piston that you posted…

• add a new statement
  If Block > Add an If
  Condition > Add a Condition
  Variable (drop down)
  $twcweather null

Since there aren’t any other subselections (e.g. $twcweather.conditions.temperature) in the variable drop down, I thought that I might have to set up some kind of new device in the SmartThings IDE, like what is required for the SmartWeather Station Tile.

How do you select the specific $twcweather subvariables?

Thanks for helping out a newbie. :^)

Try this:

• Add a new statement
• Add an IF
• Add a condition
• What to compare: Expression
• Type $twcweather.conditions.temperature in the box
• Decide on what kind of comparison
• Click on Add

[stone]

Perfect! It works great.

Try to not go overboard though please, because SmartThings is billed for each and every query. We don’t want to abuse it, because they will start charging us for this data.

The info about not querying too often would be excellent to include in the Wiki. Now I know to be conservative.

Thanks for your help!

• Brad

[WCmore]

The info about not querying too often would be excellent to include in the Wiki

I mentioned it on the $twcweather.alerts page.

[darrenofkent]

I have a piston that uses $twcweather.conditions.precip24Hour but it seems to only ever report back 0.0. We had a pile of rain the other day but it still reported 0.0. Any thoughts?

[WCmore]

Mine changes, but infrequently, and always remains a fairly low number.

I just analyzed two weeks of data, and precip24Hour was 0.00 about 95% of the time.
The highest number I saw was 0.56. (I believe it is in inches for Americans)

---

If a visual helps, there was 39 consecutive hours where it did have data… (shown below)

0.00 =  5:04 P.M.
0.01 =  6:03 P.M.  (guess 0.01 from the past hour)
0.02 =  7:03 P.M.  (guess 0.01 from the past hour)
0.03 =  8:03 P.M.  (guess 0.01 from the past hour)
0.05 =  9:04 P.M.  (guess 0.02 from the past hour)
0.08 = 10:04 P.M.  (guess 0.03 from the past hour)
0.11 = 11:04 P.M.  (guess 0.03 from the past hour)
0.13 = 12:04 A.M.  (guess 0.02 from the past hour)
0.18 =  1:04 A.M.  (guess 0.05 from the past hour)
0.22 =  2:04 A.M.  (guess 0.05 from the past hour)
0.30 =  3:04 A.M.  (guess 0.08 from the past hour)
0.33 =  4:03 A.M.  (guess 0.03 from the past hour)
0.33 =  5:03 A.M.  (guess no rain in the past hour)
0.34 =  6:04 A.M.  (guess 0.01 from the past hour)
0.39 =  7:03 A.M.  (guess 0.05 from the past hour)
0.51 =  8:03 A.M.  (guess 0.12 from the past hour)
0.55 =  9:04 A.M.  (guess 0.04 from the past hour)
0.56 = 10:03 A.M.  (guess 0.01 from the past hour)
0.55 = 11:04 A.M.  (guess no rain in the past hour)
0.55 = 12:04 P.M.  (guess no rain in the past hour)
0.55 =  1:04 P.M.  (guess no rain in the past hour)
0.55 =  2:04 P.M.  (guess no rain in the past hour)
0.55 =  3:03 P.M.  (guess no rain in the past hour)
0.55 =  4:03 P.M.  (guess no rain in the past hour)
0.55 =  5:03 P.M.  (guess no rain in the past hour)
0.55 =  6:03 P.M.  (guess no rain in the past hour)
0.55 =  7:04 P.M.  (guess no rain in the past hour)
0.54 =  8:04 P.M.  (no rain in the past hour = Notice we subtract the 0.01 from 24h ago)
0.52 =  9:03 P.M.  (no rain in the past hour = Notice we subtract the 0.02 from 24h ago)
0.49 = 10:04 P.M.  (no rain in the past hour = Notice we subtract the 0.03 from 24h ago)
0.46 = 11:04 P.M.  (no rain in the past hour = Notice we subtract the 0.03 from 24h ago)
0.43 = 12:04 A.M.  (no rain in the past hour = Notice we subtract from 24h ago)
0.40 =  1:03 A.M.  etc...
0.35 =  2:04 A.M.
0.27 =  3:03 A.M.
0.23 =  4:03 A.M.
0.22 =  5:04 A.M.
0.21 =  6:03 A.M.
0.19 =  7:04 A.M.
0.08 =  8:03 A.M.
0.00 =  9:04 A.M.  (Finally back to no rain in the past 24 hours)

Note: A few of the numbers may be off by 0.01, which is normal due to rounding.

[dejavux2]

Yikes! I’m learning all of this all over again. I am in the middle of switching over to Hubitat. ST has become unstable, and is having issues on a daily basis.