Import historical data from Weather Display

[mihec]

Hi,

I have weewx running with Davis Vantage Vue since 2019. Before that, I've been using Weather Display (2016-2019).

Is it possible to import that historical data into the same database? Or, it is more correct to do the import into a separate database file and then combine both?

I have zero knowledge about the SQL databases so apologies for my ignorance.

Thank you.

[michael.k...@gmx.at]

The WeeWX-related dimension: yes, this is possible to import the values into the same database. If the timespans overlap, you cannot create new entries for an already existing entry with a given dateTime.
The not WeeWX related dimension: did you change not only the hardware, but the location significantly? Then don't do it that way. 

[mihec]

Thank you for your reply. I will then go ahead and try with importing the data step by step (month by month) and see how it behaves (will take care of a backup first, of course). I should not have any overlap in data.

Non-WeeWX related suggestion: nothing has changed in terms of location nor hardware. I just changed the data collection software as I liked WeeWX more.

četrtek, 5. februar 2026 ob 11:27:52 UTC+1 je oseba michael.k...@gmx.at napisala:

[michael.k...@gmx.at]

don't forget to build the daily summaries for the imported data

[mihec]

I want to give feedback: the import goes on good. The daily summaries and NOAA reports are correct.

On my RPi, it takes about 6 hours for 1 year of data to import.

Thanks for help.

četrtek, 5. februar 2026 ob 12:00:21 UTC+1 je oseba michael.k...@gmx.at napisala:

[mihec]

One more related question. My 10-year database file became quite large (>1 GB). Is it safe to remove the columns which I do not need (extraTemp, etc.) ? Will this reduce the database filesize? Is there any other optimization I could/need to do?

ponedeljek, 9. februar 2026 ob 11:59:58 UTC+1 je oseba mihec napisala:

[John Smith]

Here's a thread about what I did, to save more space you also need to decrease the precision of double columns to float etc

https://groups.google.com/g/weewx-user/c/nLIdzwMGgl8/m/tXF1Y8qlAAAJ

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