Citations:ice saints

meaning the period

 * 1946, British Zone Review: A Monthly Review of Activities in the British Zone of Germany, volume 1, page 2:
 * BUCHAN's Cold Spell, or, as this terror of the market gardeners is termed in some Districts in Germany, the Ice Saints (die Eisheiligen) is nearly upon us again. The crucial nights with their dangerous frosts, threatening budding vegetation, are, the 12th, 13th and 14th of May. Millions of young plants yearly are destroyed or their growth is retarded by these three cruel nights, so aptly named in other parts of Germany “die drei gestrengen Herren” (the three cruel masters).
 * 1946, British Zone Review: A Monthly Review of Activities in the British Zone of Germany, volume 1, page 2:
 * BUCHAN's Cold Spell, or, as this terror of the market gardeners is termed in some Districts in Germany, the Ice Saints (die Eisheiligen) is nearly upon us again. The crucial nights with their dangerous frosts, threatening budding vegetation, are, the 12th, 13th and 14th of May. Millions of young plants yearly are destroyed or their growth is retarded by these three cruel nights, so aptly named in other parts of Germany “die drei gestrengen Herren” (the three cruel masters).
 * BUCHAN's Cold Spell, or, as this terror of the market gardeners is termed in some Districts in Germany, the Ice Saints (die Eisheiligen) is nearly upon us again. The crucial nights with their dangerous frosts, threatening budding vegetation, are, the 12th, 13th and 14th of May. Millions of young plants yearly are destroyed or their growth is retarded by these three cruel nights, so aptly named in other parts of Germany “die drei gestrengen Herren” (the three cruel masters).

meaning the saints

 * 1920, https://books.google.com/books?id=HyXNNcDjsmcC Monthly Weather Review], volume 47, page 563:
 * The author finds that while depressions of temperature occur in Roumania on the days of the ice saints (May 10–12) they are not a more characteristic phenomenon than depressions occurring on other dates in May.
 * 1979, David Hughes, Thomas Randle, The Rhine basin: a study of development, page 104:
 * I arrived in Koblenz, where the Mosel joins the Rhine, simultaneously with three venerable saints, namely, Mamertus, Pancratius and Servatius. Each spring the holy trio visits Germany's wine region and brings either a blessing or bad luck to the vineyards. Rhinelanders call them die Eisheiligen - the Ice Saints. The Ice Saints’ domain is as vast as it is colourful, taking in the entire German stretch of the Mosel, and all the Rhine valley, roughly between Bon and Heidelberg.
 * 1980, World Literature Today, volume 54, page 273:
 * Thus her negative judgments prove self-fulfilling. The girl is vicious, tough and sensitive — herself one of the ice saints, Pancratia, "she who fights with all means." She survives with the help of her poetry and an unsentimental, accepting aunt. The account ends, somewhat provisionally, at a turning point in the girl's life, when she moves to a boarding school run by her new family, the East German State. In keeping with the (as Arno Schmidt termed it) "porous" nature of memory,

reference

 * Albert Montefiore Hyamson, A Dictionary of English Phrases: Phraseological Allusions, Catchwords ... (1922) lists "ice saints" and "frost saints" as English phrases with this sense, as well as listing "blackthorn winter"