Interesting thing on Weather Network 7 Day forecasts
 

I look at the Weather Network's Hourly and 7 Days forecasts to have an idea of what the weather MIGHT be. Something I noticed that has me wondering. On the 7 Days forecasts the UV index is always higher at night such as now at 1AM than it is during the day. Is this usual and/or accurate or is their UV index forecast lagging by many hours?

Cheers