Since analogue meters are now read every other month, PG&E bills for an estimated usage on the off month.
The estimated gas usage on my more recent bills has been ridiculously inaccurate, having nothing to do with usage in previous years, or even the baseline 2 therms/day rate the billing clerk told me they use for estimates.
This has resulted in overly high estimated usage and thus billing me at higher tier rates, which are more expensive. If the estimates were accurate, I would've been billed at the appropriate Tier 1 rate and would not have been overcharged.
On my bill, this is more an issue with gas use than electrical use.
So, take a closer look at your bills and compare your current usage to past years. It may shed light on why your PG&E bill is so high this month (or next month).