From the LA Times "A 1944 Christmas Miracle for Gen. Patton":

On Dec. 8, Patton turned to a higher power to clear the skies. He asked Chaplain James H. O’Neill if he knew of a “good prayer for the weather,” according to military historian and Patton expert Kevin M. Hymel. “We must do something about these rains,” Patton said, “if we are to win the war.”

After some thought and research, O’Neill came up with the following: “Almighty and most merciful Father, we humbly beseech Thee, of Thy great goodness, to restrain these immoderate rains with which we have had to contend. Grant us fair weather for Battle. Graciously hearken to us as soldiers who call upon Thee that, armed with Thy power, we may advance from victory to victory and crush the oppression and wickedness of our enemies, and establish Thy justice among men and nations. Amen.”

O’Neill typed the prayer onto an index card, and on the flip side typed a Christmas greeting from Patton. Patton ordered 250,000 copies of the card printed and distributed to every man in the 3rd Army….

In December 1944, his prayer was answered. The weather miraculously cleared (it did eventually snow, but the prayer hadn’t mentioned snow), and Patton was able to get his army moving again. When the Germans launched their final attack against Allied Forces, the Battle of the Bulge, Patton swung his men north toward the town of Bastogne, where German forces surrounded American troops from the First Army. On Dec. 26, he broke through the German defenses and relieved Bastogne.