How does one use weather data in an energy market, if you don't mind my asking?

Yeah exactly like hackitup7 says, it has a huge impact on both sides of the supply and demand equation. It both drives house heating and cooling, which has a massive consumption impact, and it drives solar and wind production.

But knowing "there will be a massive drop in temperature between 1pm->2pm" doesn't help much anymore, you need to know which 15-minute or 5-minute block all those heat pumps will kick on in, to align with markets moving to 15-min and 5-min contracts.

Major forecasts like ECMWF don't have anything like that resolution; they model the planet at 3 hour time scale, with a 1 hour "reanalysis" model called ERA5.. hoping to find good info on what's available at higher resolution.

Temperature and weather can have a huge impact on power prices. Small examples:

* 90 degree day => more air conditioning usage => power goes up

* 70 degree sunny day => that's also July 4th (holiday, not a work day when factories or heavy industry are running) => lots of people go outside + it's a holiday => power consumption goes DOWN

* 10 degree difference colder/hotter => impacts resistance of power lines => impacts transmission congestion credits => impacts power prices

It's a fascinating industry. One power trading company that I consulted for had a meteorologist who was also a trader. They literally hired the dude from a news channel if I remember it correctly.

Seems like it would be pretty useful to forecast the supply of renewables (wind, solar, maybe some hydro).