I was told that the temperature in the Western Hemisphere is always rising or falling, but not constant. In early March, regardless of the ambient temperatures, the frost line begins to recede. Can you substantiate this? If so, what is the date on which the frost line begins to recede?

For much of North America, the part of winter with the coldest temperatures happens during the last week of January, into the first two weeks of February. It seems then, that after February 14, the frost line begins to move back northward for most locations in the Central/Southern United States, slowly at first, but certainly more rapidly as we get into March and April.

Most deciduous (leaf-bearing) trees in the Northern United States actually begin the process of developing leaves for the upcoming spring/summer season in mid-February; and, similarly they begin the process of changing color in mid-August. This leaf-changing process is more a function of the change in the amount of daylight as opposed to temperature.

Interestingly, during the second week of May, there comes a three-day interval known as the “The Days of the Chilly Saints” (May 11, 12 and 13). Mammertius, Pancratius and Gervatius, three early Christian saints, have feast days on these three days, which supposedly are always cold; in France, it is said that they do not pass without a frost. I suppose if you were looking to close the book on frost probabilities for the winter season, at least for temperate climates, this would be the time of the year to do it!

How did April 15 become the day that income tax is due?

Good question. Through some research we discovered that when the 16th Amendment, which allowed Congress to institute income tax, was adopted on Feb. 3, 1913, Congress actually chose March 1 as the deadline for filing returns. However, when the Revenue Act of 1918 was passed, the date was changed to March 15, without any real known reason.

The next big overhaul came in 1955 when, in addition to many tax-code revisions, the date for when taxes were due changed again, to April 15. According to many sources, the explanation for this change was because at that time the government had to pay more refunds, so it wanted more time to hold on to the money.

While some may think this change was to assist the government, the law is still in the Americans’ favor. By law, the government must mail your refund within 45 days or they have to pay interest.

Ask The Farmers’ Almanac Editors! If you have a question about the weather, gardening, history, astronomy, cooking or trivia, e-mail the Farmers’ Almanac Editors at [email protected]

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