Because they can't wear green, or this happens…
Why meteorologists can't wear green on #StPatricksDay @foxandfriends #betterwithfriends pic.twitter.com/60tPm11srR
— Dr. Maria J. Molina (@ScienceByMaria) March 17, 2014
Fox News weatherperson Maria Molina started a bit of a trend with that tweet yesterday, as her colleagues at other stations also bemoaned the fact that they couldn't join in the spirit of the day.
Here's Heather Waldman at Accuweather's effort:
Green holidays: a tv meteorologist's worst nightmare. pic.twitter.com/8PuY0W2frD
— Heather Waldman (@KCRAHeather) March 17, 2014
Seems the guys have it easier than the girls:
Yup. Green Day... Unless you are a meteorologist ... #uhoh pic.twitter.com/uY0QkeoYjL
— Josh Robbins (@imstillJosh) March 17, 2014
And another one from Lindsey Monroe of WTHI news in Indiana:
Downfall of being a meteorologist on St. Patrick's Day, green screen gets me every time I try to get in the "spirit"! pic.twitter.com/gTRlMX8xN7
— Lindsey Monroe (@LindseyWTHR13) March 17, 2014
So how do the good lads and ladies of Met Éireann deal with the problem?
Evelyn Cusack sidestepped it on last night's Six One News with a dark blue gúna and a sprig of shamrock.
Although…
There's Nuala Carey on yesterday's European weather broadcast, wearing her finest St Patrick's Day green, which blows our theory completely out of the water.
As bold as brass!
We called Montrose to get an explanation.
"It's because the chroma key screen that we use is blue," Karina Buckley of RTÉ Weather told us.
"The screens can be one of three colours - green, blue or red," she explained.
"In the US they use green a lot - which is possibily why it's known as 'green screen' - but here in the RTÉ Weather studio we use a blue one.
"Which means that we can wear green on St. Patrick's Day - but we can't ever wear blue."
So that's that cleared up then.