Sweater weather returns tonight! Are lows in the 40s normal in September?
The autumn air has arrived in North Carolina!
Locate your favorite sweater or hoodie because you will need to dress in layers this weekend. Low temperatures tonight will be the coolest we have been since the spring.
We’re forecasting 49 at Raleigh-Durham International Airport, and we haven’t seen lows in the 40s since May 16.
Clear skies, light wind, and dry air will create the perfect environment for temperatures to plummet overnight.
Low temperatures will occur around sunrise on Friday morning so you’ll want to keep your extra layer on hand for a few hours in the morning.
40s sounds chilly compared to the 90s we saw just 4 days ago but 40s in September are not uncommon.
RDU averages 2 September days with lows in the 40s and 69% of all Septembers on record in Raleigh have had at least 1 morning with a low in the 40s.
However, when you look back at the last 10 Septembers only 3 have seen lows in the 40s.
Our average low temperature this September is 64.5 which is about half a degree above normal.
This trend of warmer nights is not limited to September.
As our planet continues to warm the air can hold more moisture. Temperatures can only fall as low as the dew point at night so increasing dew points will yield increasing low temperatures.
