I have a fast internet connection, I can click on a YouTube video and instantly be watching a 30fps video in high definition with stereo sound. But if I go to weather.com and try to watch the local radar map, it slowly builds it like I’m on a 1200 baud modem and it’s 1988. It’s a 20 frame loop with no sound. What gives?
Maybe it’s independently fetching data points for each individual pixel from the weather balloon that’s reporting it?
Sorry… the only useful factual data point I can give you is that my location map loads quite quickly for me. Here’s what I’m seeing. Are you on an entirely different page, or same interface different x,y coordinates? How quickly does the link provided here load for you? Pops right up on mine and furthermore I can use the mouse wheel to zoom in and out and it does so without lag.
I tried your link, and it’s just as slow, about 15 seconds to just bring up the map, and another 15 to get the radar loop animating smoothly. Again, I have a fast connection, nothing else is slow like this. So strange. Like you, I’m guessing the radar data is dense, but still…
What’s the question here, exactly?
If it’s “why is the weather.com local radar animation slow to load?” then the answer is simple: whatever scheme they’re using for the map’s backend is kinda crappy.
Is that the central question?
I had a look at the page code, and it is not meant to be read by mortals, so I’m not sure this applies to the actual map, but there is a lot of SVG graphics happening there, meaning your browser is doing the image generation.
I’ve no idea if it’s enough to slow things down though, I think most of it is creating the surrounding frills, like the maps menu.
Another possible issue is that weather.com is to a large degree just repackaging data from weather.gov. It’s the national weather service that collects all the data and is obligated to pass it on and have an ugly web-page to make sure weather.com stays in business. That makes for a lot of potential bottlenecks and excuses for optimizing the flow of data.
Hey Tilt, what happens when you load a different data-intensive link, like this Google Maps Satellite View or something?
It seems like at least part of the problem is on your end, whether it be latency or low bandwidth or a corrupted browser cache or whatever. It takes 2 seconds on my decade-old MacBook Pro to render that radar map.
Thanks for your replies.
Edelweiss, yes, my main question is, why does the radar map at weather.com (but to some extent other weather sites as well) take what seems like an abnormally long time to load, compared to everything else on the internet.
AHunter3, that site loaded fine, in about 2 seconds. I’ve noticed the radar issue on different computers in different places. Hence my original question. It’s noticeably slower than almost anything else I encounter on the web. Maybe it’s just me, but I assumed it was something everyone dealt with.
DOn’t know about their website, but their Android app brings in weather radar animations pretty quickly. IN comparison, Weather Underground’s app is painfully slow to bring in radar animations.
It’s really impossible to say without knowing how these sites operate. But OP is entirely correct that it shouldn’t take but a second or two for a 20 frame animation to load. I wonder if the slowness happens accidentally (maybe due to way too much traffic on a server?) or on purpose to give more attention to ads?
Well it’s not loading an animation, it’s creating one from data for the map location and zoom level the user has specified.
NOAA radars site, like their satellite image site, and the Washington Post likely run COBOL on the back ends of their HTML. With modern servers, this probably requires 17 or more levels of virtual machine to get the data out.
Then again, the pages may just be collages put together in real time from a large collection of independent sub-sites. That’ll slow things down to the rate of the slowest site.
The sites have always been slow. I expect they Always will be.
I have the world’s worst Internet and I can get that and NOAA weather radar to load within a few seconds, so maybe it’s not just the radar pages that are the problem.
Of course it’s slow to load, it’s a map of the entire world 
Mine used to be slow, not sure what changed but it’s only about one second now and it keeps up with scrolling with just a tiny lag.