(WYTV) – Expect to see a full moon on Halloween night this year, but it’s also a blue moon.
About once every two and a half to three years, there are two full moons in one month–one on the 1st and the other on the 31st.
That second one is the blue moon, even though it’s not actually blue.
One theory says the blue comes from the Old English word ‘belewe,’ which means ‘to betray.’ Blue moons betray the normal schedule of full moons, so it led to the expression ‘once in a blue moon.’
The moon actually has appeared blue in the past.
After a massive volcanic eruption, the ash in the sky can sometimes block red light particles, giving the moon a bluish tint.
NASA says this happened after the Indonesian volcano, Krakatoa erupted in 1883.
October’s first full moon, the harvest moon, is coming on Thursday, October 1.
The second one, the blue moon, will peak on Saturday, October 31, so you’ll be able to see it after sunset.
Don’t miss it and hope for clear skies; a full moon on Halloween only happens once every 19 years.