Fetch data from SMHI API and manipulate said data

Hello KNIME Community,

I started using Knime a few days ago and completed the L1-DW course.

Now I want to try to fetch data from an API, which gives me information about weather in a specific geographic location.

I collect the data using a GET request, and then I want to filter the data to only display date&time and temperature. I noticed that when I try to extract Year and Months etc, it takes like 20 minutes for the node to execute even though I currently have 8700 rows to process.

My question is this: Have I approached this in a very bad way or is this time delay to be expected handling this much data?

I did a similar thing with JSON and it worked great, but the JSON only had data for like 4 months, I need more months. For reference, while I wrote this post, the GroupBy node went from 0% to 2% in the execution process.