Why is it everytime I go outside I get a runny nose, and more so when riding my bicycle? ?

You're describing two different scenarios.  If you're doing nothing while outside - as another pointed out - could be allergies.  But...I'm not a doctor, just pure speculation.  If you're cycling (especially if you're pushing it) the body is constantly trying to discharge all sorts of excess fluids - both sweat (perspiration) through pores and anything built up in your nose.  

Don't believe it?  Watch a race sometime.  You'll see riders place a finger on one side of their nose or the other & then blow snot out the opposite nostril.  I know...it's gross.  But, it happens Spring, Summer, Fall or Winter.  There's even been an article written about this back in August of 2019.  https://cyclingmagazine.ca/sections/healthnutritio...

From a Health Care point of view, here's an online article that may be of use. https://healtreatcure.org/nose/constant-runny-nose...  

This is not unusual, most likely your sinuses are sensitive to a change in environment like temperature or humidity or pollen in the air.

You can try getting some over the counter anti-histamines at the pharmacy and take one before you go out and see if it makes a difference.

Probably allergies.