On a scale between 1 and 10, the scare factor for this year’s Halloween weather is about a 3... maybe a 4 if you’re under the convergence zone in Snohomish County this morning.  Showers are decreasing this afternoon leaving us mainly dry by trick-or-treat time.  I left an isolated shower in the forecast this evening, mainly toward the Cascade foothills.  Most of you will be dry with temperatures in the mid to upper 40s.  You won’t need to put the clear plastic bag over your child’s costume as they go trick-or-treating this year!   :) 

So how scary is our Halloween weather usually?  As you can imagine, we often see rain.  We’re on the verge of November, our wettest month of the year, so we frequently receive rain on Halloween.  Looking at the past 30 years, we have seen measurable rain 57% of the time on October 31^st.  The Halloween with the most rainfall on record was in 1990 when 1.04 inches fell at Sea-Tac.  There were some thunderstorms around the sound that day, so it’s no surprise that the rainfall total was so high.  Most recently we had a soggy Halloween in 2008 (0.35”), 2005 (0.73”), and 2001 (0.44”). 

As far as temperatures go, our average high is 55 degrees for this time of year.  We’ll be slightly below that today with a forecast high of 52 degrees in Seattle.  High temperatures are usually in the 50s for the holiday.  Since records began at Sea-Tac in 1948, there have only been 7 Halloweens in the 60s.  The last one was in 1988.  The warmest on record was in 1949 when we hit a toasty 71 degrees.  That might have been a bad year to wear the gorilla costume.  Have a safe and happy Halloween! 

-Sam Argier, KIRO 7 Morning Meteorologist