Changing Data Type on Production Database - Impact

Hi,

I have a UseCase to modify the Data Types of some columns in a Table as
specified below.

How much time does it take approximately for modifying a 30GB table? Should
I perform this only during Downtime or can I do it on a Production Database?

Data Type Changes,

test=> alter table speed1 alter column expireat type date USING
expireat::date;

ALTER TABLE

test=> alter table speed1 alter column condition type jsonb[] USING
condition::jsonb[];

ALTER TABLE

test=> alter table speed1 alter column last_login type timestamp with time
zone USING last_login::timestamp with time zone;

ALTER TABLE

test=> alter table speed1 alter column remote_addr type inet USING
remote_addr::inet;

ALTER TABLE

Thanks,

Raj Kumar Narendiran.