It is possible to do it in real time, but the things you want to change can't be done through the ppfilter or the ppfilter app. They need to be done via an accompanying pure script created with a text editor that has the same name as your ppfilter. I should have made that clear. My bad. So I guess you should be looking at one of Peter's Pure scripts, not his filter.
If you have notepad++, have a look at this sample script. Now this is just a part of my own personal script. I only left the stuff in it regarding weather variables. The full script has a lot more stuff in it.
The two __PURE__add_weather_variable entries at the top define a name for the two things I want to change depending on the weather type. PP filter Brightness and PP ColorTemp. The __PURE__set_weather_variable defines a percentage or value I want to change the base number by depending on the weather. I'll get into that in a second.
We will start with ColorTemp. This line ac.setPpColorTemperatureK(6500 - weathercolortemp), sets the ppfilter colortemp to 6500 minus the value I defined above for a specific weather. For example, for Few Clouds the ppfilter color temp will be 6450 because I gave FewClouds a value of 50. So the color temp is 6500-50. For every other weather type, it will still be 6500. But you can define values for any weather type there is. I just used one type for this example.
Same goes for brightness, but done a different way. The line ac.setPpBrightness(1.00 * weatherbrightness) means brightness will be one for all weather types times the value I gave in the weather variable. In this instance, FewClouds brightness will be 1.05 because I multiplied 1 by 1.05 as set in the variable. I could have set the variable to 0.05 and made the line ac.setPpBrightness(1.00 + weatherbrightness) and accomplished the same thing.
I hope you can understand this. I'm sure there is a better way to do this, but as I mentioned above, my knowledge is limited on scripting. I do what I can. This is why I thought studying one of Peter's filters might be beneficial. He's kind of an expert on this stuff.
It is worth the time to learn how this stuff works IMO. We all have different tastes and making your own filter is the best way to get AC to look exactly how you want it. I've tried just about every filter there is and as good as they all are, none of them make AC look how I want it to look.