Why are there red highlights?

There are red highlights when there are conditions that make it potentially or obviously dangerous for flying. This includes a METAR that does not indicate VFR and temperatures and dew points that are within 2 Celcius of each other. Obviously, where and when you fly is up to you, and you alone.

Where is this data from?

Hourly forecasts are provided by the NWS API.

Winds aloft are provided by the wonderful Iowa State University Mesonet service, in particular their partnership with the NWS.

METAR and TAF information is provided by NOAA's Aviation Digital Data Service.

Location geocoding is from the Map Maker Geocoding API.

I also want to shout out the Grand Rapids office of the National Weather Service, specifically TJ, whose help was a gamechanger working on getting winds aloft forecasts.

Which areas can I get forecasts with this tool?

Due to limits in the data services that I use, this tool only works for the continental United States.

Are times local or universal?

All times are given in the local time of your device.

What about the 3000, 6000, and 9000 feet winds aloft forecasts?

The forecast data for these forecasts is generated from the same models as other winds aloft forecasts. These forecasts don't provide any more useful information than the those models and are, in fact, more location limited.

A note from Alex, creator of this website:

I created this website in my free time, originally for fun. When NOAA removed the old RUC soundings page, I reprogrammed it to get the Winds Aloft forecasts a different way. I do pay to have this website running, but I intend to keep this website free to use, and I don't want to put in the work to manage placing ads. If you get value from these forecasts, please consider buying me a coffee to help support me. If you have any feedback or ideas, please reach out to me alexnorrie1994 at gmail dot com