Frost Dates for 97503 — White City, Oregon

Half of springs at Medford Rogue Vly Airport, OR see their last 32°F night by April 8; only one in ten is past it by March 17, and one in ten still has one after April 30. Planting tender crops after April 18 leaves a 30% risk of a frost on them, after April 23 20%, and after April 30 10%. The 22 days between the even-odds date and the one-in-ten date is narrower than at 45% of the 103 Oregon 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 October 29 in half of years, as early as October 14 one year in ten, and holds off past November 16 one year in ten. A hard freeze of 28°F follows 15 days later, around November 13; in spring the one-in-ten date for 28°F is April 3, 27 days before the 32°F one. The freeze-free season lasts 204 days in a typical year, longer than at 55% of the 103 Oregon stations; it reaches 232 days one year in ten and falls short of 176 one year in ten. On average 64 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 22 days longer, to about April 30, and return around October 16. Nights of 24°F, cold enough to damage hardier plants, come in 97% of winters and 16°F in 24%.

July is the warmest month at Medford Rogue Vly Airport, OR, averaging 92°F by day and 59°F at night; December is the coldest at 46°F and 33°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 62% of years.

Warmth for growing adds up to 3,326 growing degree days a year (base 50°F), more than at 99% of the 103 Oregon stations. 31% of them (1,018) have built up by the end of June, and July adds the most, 778. Precipitation totals 18.3 inches a year, most in December (3.5") and least in July (0.2"); May to September bring 16% of it.

The nearest other station, Lost Creek Dam, OR, 17 miles northeast of White City and 283 feet higher, has a last frost 21 days later (April 29), a first frost 12 days earlier (October 17), a season 33 days shorter.

The first measurable snow (0.1 inch or more) in White City usually arrives around December 14, and the last of the season around February 13. Those are the middle dates across the winters of 1991–2020 at Medford Rogue Vly Airport, OR, 6.3 miles away: half of years saw snow earlier, half later. Snow fell in 88% of those winters. The last 32°F night of spring typically comes 54 days after the last snow.

ZIP 97503 is 6 miles from Medford Rogue Vly Airport, OR, which stands at 1,297 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 5 other ZIP codes share the station; its figures are presented in full for 97504 (Medford). The 2023 USDA Plant Hardiness Zone Map lists ZIP 97503 in zone 8b, the band where the coldest night of the year averaged 15 to 20°F (-9.4 to -6.7°C) over 1991–2020; a zone describes winter lows, not frost dates.