Looking on the internet deeply has found these results:

it has been raining since one o clock is the most popular phrase on the web.

it has been raining from one o clock 10 results on the web	it has been raining since one o clock 13 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
It doesn't look like this phrase is very popular! The search could not find any examples on the internet.	since 8 o' clock It has been raining since one o' clock. They've known each other since they ... 31 May 2009 ... It has been raining since one o' clock. They've known each other since they were at school. Posted by Juani and Carmen Rosa at 11:10 pm ... TO. since 1992 SINCE We use since + a period of time: since April They have been watching TV for two hours. It has been raining since one o' clock. They've known each other since they were at school. UNTIL, FROM

it has been raining from one o clock

10 results on the web

it has been raining since one o clock

13 results on the web

More popular!

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

since 8 o' clock It has been raining since one o' clock. They've known each other since they ...
31 May 2009 ... It has been raining since one o' clock. They've known each other since they were at school. Posted by Juani and Carmen Rosa at 11:10 pm ...
TO.
since 1992
SINCE We use since + a period of time: since April
They have been watching TV for two hours. It has been raining since one o' clock. They've known each other since they were at school. UNTIL, FROM