Late Jan/Early Feb NASA Disasters

I was just reading an article on the anniversaries of the three major
tragedies in American spaceflight. I never paid much attention to the dates
of the tragedies before. The article had the dates listed -
January 27 - Apollo 1 fire. January 28 -Challenger explosion, and February
1 - Columbia accident.

Isn't it strange that all three accidents have taken place in late
January/early February? I find this very strange. Has NASA ever considered
not launched at all in January and February? Instead of scrapping the space
shuttle just stop all missions during January thru March and they should be
safe. Maybe none of the incidents were directly caused by the January and
February weather. But still, it's kind of strange all three accidents would
take place at the same time of year.