According to IRS Publication 556 taxpayers generally must file a claim for a credit or refund within 3 years from the date you filed your original return or 2 years from the date you paid the tax, whichever is later. If you do not file a claim within this period, you may no longer be entitled to a credit or a refund.
If the due date to file a return or a claim for a credit or refund is a Saturday, Sunday, or legal holiday, it is filed on time if it is filed on the next business day. Returns you filed before the due date are considered filed on the due date. This is true even when the due date is a Saturday, Sunday, or legal holiday.
Disaster area claims for refund. If you live in a Presidentially declared disaster area or are affected by terroristic or military action, the deadline to file a claim for a refund may be postponed. This section discusses the special rules that apply to Presidentially declared disaster area refunds. A Presidentially declared disaster is a disaster that occurred in an area declared by the President to be eligible for federal assistance under the Disaster Relief and Emergency Assistance Act.
Postponed refund deadlines. The IRS may postpone for up to 1 year the deadlines for filing a claim for refund. The postponement can be used by taxpayers who are affected by a Presidentially declared disaster. The IRS may also postpone deadlines for filing income and employment tax returns, paying income and employment taxes, and making contributions to a traditional IRA or Roth IRA. For more information, see IRS Publication 547.
If any deadline is postponed, the IRS will publicize the postponement in your area and publish a news release, revenue ruling, revenue procedure, notice, announcement, or other guidance in the Internal Revenue Bulletin