Frost Dates for 97049 — Rhododendron, Oregon

Half of springs at Government Camp, OR see their last 32°F night by May 27; only one in ten is past it by May 4, and one in ten still has one after June 14. Planting tender crops after June 2 leaves a 30% risk of a frost on them, after June 8 20%, and after June 14 10%. The 18 days between the even-odds date and the one-in-ten date is narrower than at 77% of the 103 Oregon stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 9 in half of years, as early as September 18 one year in ten, and holds off past October 26 one year in ten. A hard freeze of 28°F follows 19 days later, around October 28; in spring the one-in-ten date for 28°F is May 22, 23 days before the 32°F one. The freeze-free season lasts 134 days in a typical year, shorter than at 86% of the 103 Oregon stations; it reaches 163 days one year in ten and falls short of 106 one year in ten. On average 170 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 25 days longer, to about June 21, and return around September 16. Severe cold of 16°F or below comes in 97% of winters, usually between December 15 and February 16.

August is the warmest month at Government Camp, OR, averaging 70°F by day and 48°F at night; December is the coldest at 35°F and 26°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 34% of years.

Warmth for growing adds up to 950 growing degree days a year (base 50°F), the fewest of the 103 Oregon stations. 16% of them (152) have built up by the end of June, and August adds the most, 299. Precipitation totals 89.8 inches a year, most in December (14.4") and least in July (0.9"); May to September bring 17% of it.

The nearest other station, Headworks Portland Wtr B, OR, 12 miles northwest of Rhododendron and 3,232 feet lower, has a last frost 61 days earlier (March 27), a first frost 40 days later (November 18), a season 105 days longer.

The first measurable snow (0.1 inch or more) in Rhododendron usually arrives around November 1, and the last of the season around May 14. Those are the middle dates across the winters of 1991–2020 at Government Camp, OR, 10.1 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 13 days after the last snow.

ZIP 97049 is 10 miles from Government Camp, OR, which stands at 3,980 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 97067 (Welches). The 2023 USDA Plant Hardiness Zone Map lists ZIP 97049 in zone 7b, the band where the coldest night of the year averaged 5 to 10°F (-15.0 to -12.2°C) over 1991–2020; a zone describes winter lows, not frost dates.