Is it okay to directly read from Cassandra to surface information from a web application?

I'm using Cassandra as my primary data store for a time series logging application. I receive a high-volume number of writes to this database, so Cassandra was a natural choice.

However, when I try showing statistics about the data on a web application, I make costly reads to this database and things start to slow down.

My initial idea is to run periodic cron jobs that pre-compute these statistics every hour. This would ensure no slow reads. I'm wondering if there's another way to read from a Cassandra database and what is the best solution?