Frost Dates for 77318 — Willis, Texas

Half of springs at Conroe, TX see their last 32°F night by February 24; only one in ten is past it by January 26, and one in ten still has one after March 17. Planting tender crops after March 4 leaves a 30% risk of a frost on them, after March 9 20%, and after March 17 10%. The 21 days between the even-odds date and the one-in-ten date is wider than at 50% of the 339 Texas stations behind this site's ZIP pages, so a fixed calendar date is a gamble here.

In fall the first 32°F night comes by December 2 in half of years, as early as November 11 one year in ten, and holds off past January 2 one year in ten. A hard freeze of 28°F follows 21 days later, around December 23; in spring the one-in-ten date for 28°F is March 6, 11 days before the 32°F one. The freeze-free season lasts 285 days in a typical year, longer than at 80% of the 339 Texas stations; it reaches 324 days one year in ten and falls short of 253 one year in ten. On average 17 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 March 9, and return around November 20. Nights of 24°F, cold enough to damage hardier plants, come in 58% of winters and 16°F in 4%.

August is the warmest month at Conroe, TX, averaging 96°F by day and 74°F at night; January is the coldest at 63°F and 42°F. From April to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 71% of years and March still brings one in 39% of years.

Warmth for growing adds up to 7,434 growing degree days a year (base 50°F), more than at 78% of the 351 Texas stations. 43% of them (3,162) have built up by the end of June, and August adds the most, 1,088. Precipitation totals 51.1 inches a year, most in May (5.5") and least in February (3.3"); May to September bring 43% of it.

The nearest other station, Conroe Montgomery Co Airport, TX, 10 miles southeast of Willis, has a last frost 15 days later (March 11), a first frost 13 days earlier (November 19), a season 32 days shorter.

Measurable snow is rare here: only 0 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Conroe, TX, 8.2 miles away, so there is no typical first-snow date to plan around.

ZIP 77318 is 8 miles from Conroe, TX, which stands at 245 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 7 other ZIP codes share the station; its figures are presented in full for 77304 (Conroe). The 2023 USDA Plant Hardiness Zone Map lists ZIP 77318 in zone 9a, the band where the coldest night of the year averaged 20 to 25°F (-6.7 to -3.9°C) over 1991–2020; a zone describes winter lows, not frost dates.