The giving season is here. While most nonprofit agencies receive gifts year-round, most also get 15 percent or more of those gifts in December, according to Blackbaud, the developer of software and supplier of services for nonprofits.

The holiday spirit and the end of the tax year combine to persuade Americans to open their wallets more widely than, say, in August. The season also sees an uptick in more hands-on volunteer efforts. People step up to help deliver food baskets and take part in other efforts to assist those less fortunate.

If there’s a downside to the holiday season generosity, it’s this: While gifts of money can be used whenever the need for them is greatest, gifts of time must be used when the donors make them available. A food bank or other institution cannot simply stuff would-be volunteers into a closet to be pulled out six months later when their services are needed.

So if you’re inclined to give money to your favorite worthy cause this month, by all means do so. That cause is no doubt counting on you and your gift.

If it’s time you have to give, you might check first. Some agencies are hard-pressed to put volunteers to use in winter months; knowing that might persuade you to put off your gift of time until it’s needed by the agency you’re trying to help.