A study released in late January showed that, nationally, car insurance policies purchased in December were 8 percent cheaper than polices that were purchased in March, the most expensive month. The yearlong study, conducted by InsuranceQuotes.com, couldn’t pinpoint a cause for the variance. However, the report did note that rate increases and inflation adjustments often take effect in January.
Furthermore, rates varied widely by state. In Washington, rates varied 14.1 percent from the highest month—March--to the lowest month, which was not specified. The average monthly cost in the Evergreen State is $94, compared to $99 per month nationally. The biggest fluctuation was in Hawaii, where rates were 48 percent lower in December than they were in March.
The National Association of Insurance Commissioners (NAIC) said many factors could be at play, including weather patterns, risks and costs that differ by state and even zip codes within a state, and changes in state law that may affect rates.