IRA CD rates can vary greatly among the traditional and online banks and credit unions that offer them to investors. Getting into an IRA CD is an excellent option for anyone wishing to set money aside in a safe place and earn interest on their investment at the same time. But there are some important variables to think about that can greatly impact the financial return on an IRA certificate of deposit.Major Factors Influencing CD RatesMany such variables exist, but a few in particular tend to come into play most often for investors. One of them is the fixed term of investment, or the length of time to maturity for the IRA CD. Longer terms tie up investors' money for a more significant period of time, and financial institutions offer higher rates in return for the ability to use the principal for a longer stretch.Those who are looking for the best IRA CD rates have to weigh the possibility of higher rates against the prospect of having their principal essentially unavailable for a longer duration. For example, a 10-year IRA CD will tend to offer much higher rates than a certificate of deposit spanning only a handful of months. The trade-off, of course, is that the principal is not readily available and is tied down for a much longer duration.Penalties and CD RatesIt is possible in most cases to access the principal invested in an IRA CD prior to maturity, but it usually comes at a steep price. This is another very important factor to consider when shopping around for the best IRA CD interest rates. It is great to find a vehicle that offers a high yield, but any early withdrawal penalties need to be factored in.The best rates for IRA certificates of deposit often come from financial institutions that offer investors the most flexibility as far as the term of the investment and penalties attached. With many different options on the market, wise investors will choose carefully based on the factors they find most important. Finding the best IRA CD rates allows investors to safely position their principal investment for predictable income.