Daylight Saving Time - are you configured for it?

[overeasy]

Just a reminder that DST goes into effect this Sunday, March 10 at 2:00am local standard time.

Since we last changed the clocks, IoTaWatt has been enhanced to support automatic DST time adjustment. To enable the automatic adjustment, you should set the time zone to the time offset for your local standard time. For EST that’s UTC-5, CST UTC-6… etc.

Then check the box “Allow Daylight Time” and save. Then cross your fingers.

If you are using PVoutput, this is especially important because IoTaWatt stamps the data with local time.

[AhrBee]

PST = UTC-8
MST = UTC-7

Then there are locations that don’t observe daylight savings time (Arizona in the States). I prefer to stick with UTC on my computers.

[overeasy]

Thanks for picking up that error with PST. To be clear, you can specify one of these time zones and not use DST if it doesn’t apply.

[llamafilm]

I’m glad you posted this. I was confused about the time. I’m in Pacific timezone, and when I first setup IotaWatt, I mistakenly set it for -7 and ticked the box for daylight time. It seemed ok because in all the graph views, when I set to standard views like “today” the X axis always ended at the current, correct time. But I started noticing a 1hr discrepancy, so then I figured out I actually need to set it to -8 in the IotaWatt setup.
I’m curious, why does the X axis look correct even when this timezone is set wrong? I would have expected it to end 1hr later. I’m guessing some part of this uses the timestamp from your web browser?

Here’s the old graph set to “today” time period

And here’s it is after I fixed the timezone

Before, it was starting the day at 23:00, which makes the grid_import about 500Wh too high.

[overeasy]

Believe it or not time-zones and in particular DST and BST are one of the thorniest issues to deal with in programming a user interface. It seems so simple to the average person.

IoTaWatt maintains the datalog using NTP (GMT) time. That is available with high precision from internet time servers and is consistent everywhere on earth. There are three places where local time is used inside IoTaWatt:

The datalog messages are timestamped with local time.

Uploads to PVoutput must be stamped with local time.

Queries with relative begin and/or end periods use local time. Think “today”.

Most times displayed in the browser app get NPT time from IoTaWatt and are converted to local time per your browser or computer timezone setting.

[khaney]

To be clear, if I’m on the east coast US (currently now DST), should I have -4 here or -5? I’m thinking it should be -5, but now not sure if the checkbox is making it -4?

[overeasy]

Out time zone is Eastern Time. Depending on time of year the time will be

-5 Eastern Standard Time (EST)
or
-4 Eastern Daylight Time. (EDT)

So to be clear, you should set Time Zone to -4 and check the “Allow Daylight Time” box.

[khaney]

I don’t think I ever realized it’s actually EDT not DST! makes sense though since it’s not just an Eastern time zone thing!

thanks