Why has my ping suddenly gone up by 30?

20 or 50. No way you will tell difference.

Somatri is right. That difference is not noticeable except for the number on your screen.

To answer your question however... It is impossible to say. There are an infinite number of possibilities. Several of the most common...

1. Your ISP is having higher than usual ping and thus your communication with the Riot servers is slower than expected.
2. Something has changed in your environment. You are downloading something whether you know it or not. While someone downloading something shouldnt effect your ping, it sadly does thanks to terrible modems / terrible connection sharing.
3. you are comparing data from two different days and different times. You will have lower ping if you played at 9 am on a Wednesday than if you played at 7pm on a Saturday. You can't compare these numbers and wonder why you get different results.

i wish i still got ping that low :( its between 70-100 for me usually. #neededaminipityparty #feelsbadman

reto moved their servers.

I have the same problem I've gone from around 30-34 to 60-63 :/