Frost Dates for 65559 — Saint James, Missouri

Half of springs at Rolla Missouri S&T, MO see their last 32°F night by April 5; only one in ten is past it by March 21, and one in ten still has one after April 22. Planting tender crops after April 11 leaves a 30% risk of a frost on them, after April 16 20%, and after April 22 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 66% of the 158 Missouri stations behind this site's ZIP pages.

In fall the first 32°F night comes by November 1 in half of years, as early as October 18 one year in ten, and holds off past November 15 one year in ten. A hard freeze of 28°F follows 9 days later, around November 10; in spring the one-in-ten date for 28°F is April 10, 12 days before the 32°F one. The freeze-free season lasts 207 days in a typical year, longer than at 87% of the 158 Missouri stations; it reaches 231 days one year in ten and falls short of 188 one year in ten. On average 96 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 13 days longer, to about April 18, and return around October 21. Severe cold of 16°F or below comes every winter, usually between December 11 and February 28.

July is the warmest month at Rolla Missouri S&T, MO, averaging 89°F by day and 69°F at night; January is the coldest at 41°F and 22°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 64% of years.

Warmth for growing adds up to 4,294 growing degree days a year (base 50°F), more than at 81% of the 158 Missouri stations. 37% of them (1,572) have built up by the end of June, and July adds the most, 893. Precipitation totals 47.3 inches a year, most in May (5.5") and least in February (2.5"); May to September bring 49% of it.

The nearest other station, Vichy Rolla National Airport, MO, 12 miles northwest of Saint James, has a last frost 7 days later (April 12), a first frost 7 days earlier (October 25), a season 13 days shorter.

The first measurable snow (0.1 inch or more) in Saint James usually arrives around November 30, and the last of the season around March 24. Those are the middle dates across the winters of 1991–2020 at Rolla Missouri S&T, MO, 9.7 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 12 days after the last snow.

ZIP 65559 is 10 miles from Rolla Missouri S&T, MO, which stands at 1,173 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 65401 (Rolla). The 2023 USDA Plant Hardiness Zone Map lists ZIP 65559 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.