Heppner, Oregon climate: Normal weather by month, frost dates and records
Heppner's normal year runs from 27°F December nights to 87°F July afternoons, with 13.1 inches of precipitation and 13 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.9°C, December lows of −3°C, July highs of 30°C, 332 mm of precipitation a year.
- NOAA stationHeppner
- Station IDUSC00353827
- Location45.37°N 119.56°W
- Elevation1,885 ft (575 m)
- Population1,119
On October 23, the normal high in Heppner is 60°F and the normal low 37°F, and the chance of measurable rain or snow is 29%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Heppner.
- Jan 44° 28°
- Feb 47° 29°
- Mar 55° 34°
- Apr 61° 38°
- May 69° 45°
- Jun 77° 50°
- Jul 87° 55°
- Aug 86° 55°
- Sep 77° 48°
- Oct 64° 40°
- Nov 51° 32°
- Dec 43° 27°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Heppner each month?
July is the warmest month, with normal highs of 87°F; December the coldest, with normal lows of 27°F. The most precipitation falls in May (1.71 in), the least in August (0.28 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 44°F | 28°F | 35.6°F | 1.32 | 3.0 | 11 | <1 | 22 | 9 h 10 min |
| February | 47°F | 29°F | 38.3°F | 1.07 | 3.4 | 10 | <1 | 19 | 10 h 20 min |
| March | 55°F | 34°F | 44.2°F | 1.36 | 0.9 | 12 | <1 | 14 | 11 h 50 min |
| April | 61°F | 38°F | 49.3°F | 1.46 | 0.1 | 11 | <1 | 6 | 13 h 30 min |
| May | 69°F | 45°F | 56.9°F | 1.71 | 0.0 | 10 | 1 | 1 | 14 h 50 min |
| June | 77°F | 50°F | 63.1°F | 1.35 | 0.0 | 7 | 3 | <1 | 15 h 40 min |
| July | 87°F | 55°F | 71.0°F | 0.31 | 0.0 | 3 | 12 | <1 | 15 h 20 min |
| August | 86°F | 55°F | 70.4°F | 0.28 | 0.0 | 2 | 11 | <1 | 14 h 10 min |
| September | 77°F | 48°F | 62.8°F | 0.43 | 0.0 | 4 | 2 | <1 | 12 h 40 min |
| October | 64°F | 40°F | 51.7°F | 1.17 | 0.2 | 9 | <1 | 5 | 11 h |
| November | 51°F | 32°F | 41.6°F | 1.37 | 0.9 | 12 | <1 | 15 | 9 h 30 min |
| December | 43°F | 27°F | 34.9°F | 1.26 | 4.3 | 12 | <1 | 23 | 8 h 50 min |
| Year (annual) | 63°F | 40°F | 51.6°F | 13.09 | 12.8 | 102 | 28 | 106 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 6°C | −2°C | 2.0°C | 34 mm | 8 cm |
| February | 9°C | −2°C | 3.5°C | 27 mm | 9 cm |
| March | 13°C | 1°C | 6.8°C | 35 mm | 2 cm |
| April | 16°C | 3°C | 9.6°C | 37 mm | 0 cm |
| May | 21°C | 7°C | 13.8°C | 43 mm | 0 cm |
| June | 25°C | 10°C | 17.3°C | 34 mm | 0 cm |
| July | 30°C | 13°C | 21.7°C | 8 mm | 0 cm |
| August | 30°C | 13°C | 21.3°C | 7 mm | 0 cm |
| September | 25°C | 9°C | 17.1°C | 11 mm | 0 cm |
| October | 18°C | 4°C | 10.9°C | 30 mm | 1 cm |
| November | 11°C | 0°C | 5.3°C | 35 mm | 2 cm |
| December | 6°C | −3°C | 1.6°C | 32 mm | 11 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00353827; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Heppner?
Normal highs sit between 65°F and 85°F in May, June and September. Of those, September has the fewest days with rain (4).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00353827.
When is the last frost in Heppner?
In Heppner, the last spring frost (32°F) comes after April 26 in half of years and after May 11 in one year in ten; the first autumn frost comes before October 19 in half of years and before October 3 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 261 year in 10 after May 11; 9 in 10 after April 6
- First autumn frost, half of years before
- October 191 year in 10 before October 3; 9 in 10 before November 2
NOAA puts the median frost-free season at 174 days, and the season without a hard freeze (28°F) at 210 days.
A hard freeze (28°F) comes after April 2 in half of springs and before November 1 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Heppner in zone 7a in ZIP code 97836, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Heppner's NOAA station is in zone 7b: the coldest night of a typical year reaches 5°F (25 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Oregon · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00353827; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Heppner?
In a normal year in Heppner, 28 days a year reach 90°F (2 of them 100°F or more), 106 nights fall to 32°F or colder and 102 days bring measurable precipitation.
- Days at 90°F or more
- 28a normal year
- Days at 100°F or more
- 2a normal year
- Nights at 32°F or colder
- 106a normal year
- Days that stay below freezing
- 15high of 32°F or less
- Days with 0.01 inch of precipitation
- 102a normal year
- Days with 1 inch of snow or more
- 6a normal year
The highest temperature in this station's record (since 1893) is 110°F, on August 10, 1898; the lowest is −19°F, on January 12, 1909.
The wettest calendar year on that record is 1942, with 19.08 in; the snowiest season is 1949–50, with 46.4 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00353827; records: ACIS (NOAA Regional Climate Centers), station USC00353827. Records use complete months only; a month missing more than three days is left out.
How sunny is Heppner?
Over a year 78% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Heppner, 4.2 kWh per square metre a day. July is the sunniest month (93%) and December the cloudiest (56%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 59% | 1.4 |
| February | 65% | 2.3 |
| March | 68% | 3.5 |
| April | 74% | 5.2 |
| May | 77% | 6.2 |
| June | 82% | 7.1 |
| July | 93% | 7.7 |
| August | 91% | 6.5 |
| September | 86% | 4.8 |
| October | 76% | 3.0 |
| November | 64% | 1.6 |
| December | 56% | 1.1 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Heppner need?
A normal year in Heppner brings 5,380 heating degree days, 0% more than the median U.S. place (5,373), and 531 cooling degree days, 41% fewer than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 2,521 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 911 | 0 |
| February | 748 | 0 |
| March | 646 | 0 |
| April | 472 | 1 |
| May | 268 | 18 |
| June | 117 | 58 |
| July | 23 | 207 |
| August | 20 | 187 |
| September | 123 | 57 |
| October | 417 | 3 |
| November | 702 | 0 |
| December | 935 | 0 |
| Year (annual) | 5,380 | 531 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00353827. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Heppner been warmer than normal lately?
2025 averaged 51.9°F, 0.3°F above the 1991-2020 normal of 51.6°F. 2 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 52.8°F | +1.2°F | 9.60 | 36.0 |
| 2022 | 50.5°F | −1.1°F | 15.18 | 18.5 |
| 2023 | 51.4°F | −0.2°F | 11.26 | 4.5 |
| 2025 | 51.9°F | +0.3°F | 11.51 | 8.7 |
Over 103 complete years from 1890 to 2023, the station's annual mean temperature rose at a fitted 2.8°F per century (+0.16°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00353827; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Heppner's climate compare?
Heppner is warmer than 48 of the other 104 places with their own NOAA record in Oregon, and wetter than 17. Across the 7,247 U.S. stations with normals, its annual mean of 51.6°F is warmer than 48%.
In the Köppen classification computed from these normals, Heppner is BSk: cold semi-arid steppe. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Heppner share this climate record?
2 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Ione, OR328 people · 16 mi NW
- Lexington, OR226 people · 8 mi NW
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Heppner's climate
What is the coldest month in Heppner?
December, with a normal high of 43°F and a normal low of 27°F. The warmest is July (87°F by day, 55°F at night).
Does it snow in Heppner?
Yes: 13 inches in a normal year, falling on 8 days with 0.1 inch or more, the most in December (4.3 inches).
What is the rainiest month in Heppner?
May, with 1.71 in of precipitation in a normal year; the driest is August with 0.28 in.
What plant hardiness zone is Heppner in?
The USDA's 2023 map puts Heppner in zone 7a in ZIP code 97836, the nearest ZIP area. By the same method at Heppner's NOAA station, the coldest night of a typical year reaches 5°F (25 years, 1991-2020): zone 7b.
How late can frost come in Heppner?
In half of years the last 32°F night comes after April 26; in one year in ten it comes after May 11. Waiting until May 11 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Oregon climateThe statewide normals and every place in the state
- Condon, OR31 miles from this station, 49.0°F a year
- Boardman, OR34 miles from this station, 54.0°F a year
- Hermiston, OR35 miles from this station, 53.9°F a year
- Pilot Rock, OR37 miles from this station, 51.9°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made