The weather underground sticker is useful. But the NOAA weather forecast is available all the way to the summit during climbing season (May-July) and of course there’s the Denali Pass weather station that they want to maintain just below the summit at 18,700 feet.
The International Arctic Center has made much of a weather station just below the summit at 18,700 feet on Denali Pass. But the station does not function year round. You can get the latest here.
NOAA report for Mount McKinley During May-July Climbing Season (breakout of iframe)