Mud Mountain Dam, Washington climate: Climate normals at a NOAA weather station
Mud Mountain Dam's normal year runs from 33°F December nights to 76°F August afternoons, with 60.1 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.9°C, December lows of 0°C, August highs of 24°C, 1,527 mm of precipitation a year.
- NOAA stationMud Mountain Dam
- Station IDUSC00455704
- Location47.14°N 121.94°W
- Elevation1,308 ft (399 m)
On October 23, the normal high in Mud Mountain Dam is 57°F and the normal low 41°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Mud Mountain Dam.
- Jan 46° 33°
- Feb 47° 33°
- Mar 51° 35°
- Apr 56° 38°
- May 63° 44°
- Jun 67° 48°
- Jul 75° 52°
- Aug 76° 52°
- Sep 70° 48°
- Oct 59° 42°
- Nov 50° 36°
- Dec 45° 33°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Mud Mountain Dam each month?
August is the warmest month, with normal highs of 76°F; December the coldest, with normal lows of 33°F. The most precipitation falls in November (8.02 in), the least in July (1.50 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 46°F | 33°F | 39.4°F | 7.04 | – | <1 | 15 | 8 h 50 min |
| February | 47°F | 33°F | 40.3°F | 5.18 | – | <1 | 14 | 10 h 20 min |
| March | 51°F | 35°F | 42.9°F | 6.61 | – | <1 | 13 | 11 h 50 min |
| April | 56°F | 38°F | 46.7°F | 5.60 | – | <1 | 6 | 13 h 30 min |
| May | 63°F | 44°F | 53.0°F | 4.99 | – | <1 | 1 | 15 h |
| June | 67°F | 48°F | 57.6°F | 3.87 | – | <1 | <1 | 15 h 50 min |
| July | 75°F | 52°F | 63.3°F | 1.50 | – | 1 | <1 | 15 h 30 min |
| August | 76°F | 52°F | 63.9°F | 1.65 | – | 1 | <1 | 14 h 20 min |
| September | 70°F | 48°F | 58.9°F | 3.37 | – | <1 | <1 | 12 h 40 min |
| October | 59°F | 42°F | 50.5°F | 6.00 | – | <1 | 3 | 11 h |
| November | 50°F | 36°F | 43.2°F | 8.02 | – | <1 | 10 | 9 h 20 min |
| December | 45°F | 33°F | 38.6°F | 6.30 | – | <1 | 17 | 8 h 30 min |
| Year (annual) | 59°F | 41°F | 49.9°F | 60.13 | – | 3 | 79 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 8°C | 1°C | 4.1°C | 179 mm |
| February | 9°C | 1°C | 4.6°C | 132 mm |
| March | 10°C | 2°C | 6.1°C | 168 mm |
| April | 13°C | 3°C | 8.2°C | 142 mm |
| May | 17°C | 6°C | 11.7°C | 127 mm |
| June | 20°C | 9°C | 14.2°C | 98 mm |
| July | 24°C | 11°C | 17.4°C | 38 mm |
| August | 24°C | 11°C | 17.7°C | 42 mm |
| September | 21°C | 9°C | 14.9°C | 86 mm |
| October | 15°C | 6°C | 10.3°C | 152 mm |
| November | 10°C | 2°C | 6.2°C | 204 mm |
| December | 7°C | 0°C | 3.7°C | 160 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Buckley (4 miles away), gets 4 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00455704; 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.
Which months are mildest at Mud Mountain Dam?
Normal highs sit between 65°F and 85°F in June, July, August and September.
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 USC00455704.
When is the last frost at Mud Mountain Dam?
In Mud Mountain Dam, the last spring frost (32°F) comes after April 18 in half of years and after May 10 in one year in ten; the first autumn frost comes before October 31 in half of years and before October 8 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 181 year in 10 after May 10; 9 in 10 after March 28
- First autumn frost, half of years before
- October 311 year in 10 before October 8; 9 in 10 before November 21
NOAA puts the median frost-free season at 196 days, and the season without a hard freeze (28°F) at 247 days.
A hard freeze (28°F) comes after March 15 in half of springs and before November 17 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Mud Mountain Dam in zone 8b in ZIP code 98396, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 8a: the coldest night of a typical year reaches 15°F (22 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 Washington · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00455704; 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 at Mud Mountain Dam?
In a normal year in Mud Mountain Dam, 3 days a year reach 90°F and 79 nights fall to 32°F or colder.
- Days at 90°F or more
- 3a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 79a normal year
- Days that stay below freezing
- 6high of 32°F or less
The highest temperature in this station's record (since 1939) is 107°F, on June 29, 2021; the lowest is −2°F, on January 14, 1950.
The wettest calendar year on that record is 1975, with 74.93 in; the snowiest season is 1968–69, with 70.8 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00455704; records: ACIS (NOAA Regional Climate Centers), station USC00455704. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Mud Mountain Dam?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds at Mud Mountain Dam, 3.8 kWh per square metre a day. July is the sunniest month (86%) and December the cloudiest (54%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 56% | 1.2 |
| February | 64% | 2.1 |
| March | 63% | 3.1 |
| April | 67% | 4.6 |
| May | 70% | 5.7 |
| June | 74% | 6.3 |
| July | 86% | 7.0 |
| August | 85% | 5.9 |
| September | 79% | 4.3 |
| October | 69% | 2.5 |
| November | 58% | 1.3 |
| December | 54% | 0.9 |
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 many heating and cooling degree days does Mud Mountain Dam record?
A normal year at Mud Mountain Dam brings 5,652 heating degree days, 5% more than the median U.S. place (5,373), and 153 cooling degree days, 83% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,654 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 794 | 0 |
| February | 692 | 0 |
| March | 684 | 0 |
| April | 548 | 1 |
| May | 376 | 6 |
| June | 239 | 17 |
| July | 106 | 54 |
| August | 89 | 55 |
| September | 203 | 20 |
| October | 449 | 1 |
| November | 654 | 0 |
| December | 820 | 0 |
| Year (annual) | 5,652 | 153 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00455704. 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.
Have recent years at Mud Mountain Dam been warmer than normal?
2025 averaged 51.4°F, 1.5°F above the 1991-2020 normal of 49.9°F. 4 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 50.1°F | +0.2°F | 60.81 |
| 2023 | 50.7°F | +0.8°F | – |
| 2024 | 51.1°F | +1.2°F | – |
| 2025 | 51.4°F | +1.5°F | – |
Over 71 complete years from 1940 to 2025, the station's annual mean temperature rose at a fitted 2.7°F per century (+0.15°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00455704; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Mud Mountain Dam's climate compare?
Mud Mountain Dam is warmer than 37 of the 96 places with their own NOAA record in Washington, and wetter than 74. Across the 7,247 U.S. stations with normals, its annual mean of 49.9°F is warmer than 40%.
In the Köppen classification computed from these normals, Mud Mountain Dam is Csb: temperate, dry-summer, warm summer. 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 Mud Mountain Dam share this climate record?
Greenwater has no NOAA station with 1991-2020 normals of its 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.
- Greenwater, WA138 people · 14 mi E
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 Mud Mountain Dam's climate
What is the coldest month at Mud Mountain Dam?
December, with a normal high of 45°F and a normal low of 33°F. The warmest is August (76°F by day, 52°F at night).
Does it snow at Mud Mountain Dam?
Yes. NOAA publishes no 1991-2020 snowfall normal for the station; the nearest record that keeps one, Buckley (4 miles away), records 4 inches of snow in a normal year.
What is the rainiest month at Mud Mountain Dam?
November, with 8.02 in of precipitation in a normal year; the driest is July with 1.50 in.
What plant hardiness zone is Mud Mountain Dam in?
The USDA's 2023 map puts Mud Mountain Dam in zone 8b in ZIP code 98396, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 15°F (22 years, 1991-2020): zone 8a.
How late can frost come at Mud Mountain Dam?
In half of years the last 32°F night comes after April 18; in one year in ten it comes after May 10. Waiting until May 10 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Washington climateThe statewide normals and every place in the state
- Buckley, WA4 miles from this station, 50.9°F a year
- Palmer (3 mi ESE), WA12 miles from this station, 50.4°F a year
- McMillin, WA15 miles from this station, 50.5°F a year
- Landsburg, WA16 miles from this station, 50.5°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made