McMillin, Washington climate: Normal weather by month, frost dates and records
McMillin's normal year runs from 33°F December nights to 77°F August afternoons, with 45.1 inches of precipitation and 6 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.3°C, December lows of 0°C, August highs of 25°C, 1,146 mm of precipitation a year.
- NOAA stationMcMillin Reservoir
- Station IDUSC00455224
- Location47.14°N 122.26°W
- Elevation579 ft (177 m)
- From the center1 miles
- Population (census place)1,298
On October 14, the normal high in McMillin is 60°F and the normal low 42°F, and the chance of measurable rain or snow is 45%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for McMillin.
- Jan 46° 33°
- Feb 48° 33°
- Mar 52° 36°
- Apr 57° 39°
- May 64° 45°
- Jun 69° 49°
- Jul 76° 52°
- Aug 77° 53°
- 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 in McMillin each month?
August is the warmest month, with normal highs of 77°F; December the coldest, with normal lows of 33°F. The most precipitation falls in November (7.06 in), the least in August (0.90 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 46°F | 33°F | 39.7°F | 6.12 | 1.5 | 20 | <1 | 13 | 8 h 50 min |
| February | 48°F | 33°F | 40.6°F | 4.33 | 0.5 | 15 | <1 | 13 | 10 h 20 min |
| March | 52°F | 36°F | 44.0°F | 4.80 | 0.6 | 20 | <1 | 9 | 11 h 50 min |
| April | 57°F | 39°F | 48.0°F | 3.90 | 0.0 | 16 | <1 | 2 | 13 h 30 min |
| May | 64°F | 45°F | 54.4°F | 2.97 | 0.0 | 13 | <1 | <1 | 15 h |
| June | 69°F | 49°F | 59.0°F | 2.28 | 0.0 | 11 | <1 | <1 | 15 h 50 min |
| July | 76°F | 52°F | 64.0°F | 0.92 | 0.0 | 5 | 1 | <1 | 15 h 30 min |
| August | 77°F | 53°F | 64.5°F | 0.90 | 0.0 | 5 | 1 | <1 | 14 h 20 min |
| September | 70°F | 48°F | 58.9°F | 1.78 | 0.0 | 8 | <1 | <1 | 12 h 40 min |
| October | 59°F | 42°F | 50.4°F | 4.08 | 0.0 | 15 | <1 | 2 | 11 h |
| November | 50°F | 36°F | 43.2°F | 7.06 | 1.5 | 19 | <1 | 8 | 9 h 20 min |
| December | 45°F | 33°F | 39.0°F | 5.99 | 1.5 | 20 | <1 | 14 | 8 h 30 min |
| Year (annual) | 59°F | 42°F | 50.5°F | 45.13 | 5.6 | 166 | 3 | 60 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 8°C | 1°C | 4.3°C | 155 mm | 4 cm |
| February | 9°C | 1°C | 4.8°C | 110 mm | 1 cm |
| March | 11°C | 2°C | 6.7°C | 122 mm | 2 cm |
| April | 14°C | 4°C | 8.9°C | 99 mm | 0 cm |
| May | 18°C | 7°C | 12.4°C | 75 mm | 0 cm |
| June | 21°C | 9°C | 15.0°C | 58 mm | 0 cm |
| July | 24°C | 11°C | 17.8°C | 23 mm | 0 cm |
| August | 25°C | 11°C | 18.1°C | 23 mm | 0 cm |
| September | 21°C | 9°C | 14.9°C | 45 mm | 0 cm |
| October | 15°C | 5°C | 10.2°C | 104 mm | 0 cm |
| November | 10°C | 2°C | 6.2°C | 179 mm | 4 cm |
| December | 7°C | 0°C | 3.9°C | 152 mm | 4 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00455224; 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 McMillin?
Normal highs sit between 65°F and 85°F in June, July, August and September. Of those, August has the fewest days with rain (5).
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 USC00455224.
When is the last frost in McMillin?
In McMillin, the last spring frost (32°F) comes after April 11 in half of years and after April 29 in one year in ten; the first autumn frost comes before October 30 in half of years and before October 13 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 111 year in 10 after April 29; 9 in 10 after March 23
- First autumn frost, half of years before
- October 301 year in 10 before October 13; 9 in 10 before November 17
NOAA puts the median frost-free season at 202 days, and the season without a hard freeze (28°F) at 244 days.
A hard freeze (28°F) comes after March 16 in half of springs and before November 14 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts McMillin in zone 8b in ZIP code 98374, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, McMillin's NOAA station is in zone 8b: the coldest night of a typical year reaches 18°F (21 complete years).
Frost dates for every NOAA station in Washington · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00455224; 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 McMillin?
In a normal year in McMillin, 3 days a year reach 90°F, 60 nights fall to 32°F or colder and 166 days bring measurable precipitation.
- 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
- 60a normal year
- Days that stay below freezing
- 2high of 32°F or less
- Days with 0.01 inch of precipitation
- 166a normal year
- Days with 1 inch of snow or more
- 2a normal year
The highest temperature in this station's record (since 1941) is 102°F, on July 30, 2009; the lowest is −1°F, on December 23, 1983.
The wettest calendar year on that record is 1996, with 62.88 in; the snowiest season is 1949–50, with 41.7 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00455224; records: ACIS (NOAA Regional Climate Centers), station USC00455224. Records use complete months only; a month missing more than three days is left out.
How sunny is McMillin?
Over a year 67% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around McMillin, 3.4 kWh per square metre a day. August is the sunniest month (78%) and December the cloudiest (51%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 52% | 1.0 |
| February | 60% | 1.9 |
| March | 58% | 2.9 |
| April | 63% | 4.2 |
| May | 66% | 5.3 |
| June | 68% | 5.7 |
| July | 78% | 6.3 |
| August | 78% | 5.4 |
| September | 74% | 3.9 |
| October | 63% | 2.3 |
| November | 54% | 1.2 |
| December | 51% | 0.8 |
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 McMillin need?
A normal year in McMillin brings 5,397 heating degree days, 0% more than the median U.S. place (5,373), and 120 cooling degree days, 87% 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 1,715 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 784 | 0 |
| February | 685 | 0 |
| March | 650 | 0 |
| April | 510 | 0 |
| May | 331 | 3 |
| June | 192 | 12 |
| July | 78 | 48 |
| August | 63 | 49 |
| September | 191 | 8 |
| October | 453 | 0 |
| November | 654 | 0 |
| December | 807 | 0 |
| Year (annual) | 5,397 | 120 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00455224. 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.
How does McMillin's climate compare?
McMillin is warmer than 46 of the other 95 places with their own NOAA record in Washington, and wetter than 63. Across the 7,247 U.S. stations with normals, its annual mean of 50.5°F is warmer than 43%.
In the Köppen classification computed from these normals, McMillin 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 McMillin share this climate record?
23 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.
- South Hill, WAalso near: Tacoma #1 (11 mi, 53.7°F a year); Buckley (14 mi, 50.9°F a year)68,161 people · 2 mi SW
- Puyallup, WA42,552 people · 3 mi NW
- Graham, WA35,090 people · 7 mi S
- Spanaway, WA34,322 people · 8 mi W
- Frederickson, WA24,219 people · 6 mi SW
- Bonney Lake, WA22,145 people · 6 mi NE
- Elk Plain, WA13,863 people · 8 mi SW
- Lake Tapps, WA12,360 people · 8 mi NE
- Prairie Ridge, WA12,054 people · 6 mi E
- Sumner, WA10,885 people · 6 mi N
- Summit View, WA9,014 people · 5 mi W
- Orting, WA8,911 people · 3 mi SE
- Summit, WA8,885 people · 6 mi NW
- Clover Creek, WA7,128 people · 6 mi W
- Tehaleh, WA6,769 people · 4 mi E
- Eatonville, WA2,864 people · 19 mi S
- Alderton, WA2,857 people · 3 mi NE
- South Creek, WA1,885 people · 11 mi SW
- North Puyallup, WA1,363 people · 4 mi N
- Clear Lake, WA1,266 people · 15 mi S
- Crocker, WA1,173 people · 7 mi SE
- Roy, WA803 people · 17 mi SW
- Kapowsin, WA449 people · 12 mi S
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 McMillin's climate
What is the coldest month in McMillin?
December, with a normal high of 45°F and a normal low of 33°F. The warmest is August (77°F by day, 53°F at night).
Does it snow in McMillin?
Yes: 6 inches in a normal year, falling on 4 days with 0.1 inch or more, the most in January (1.5 inches).
What is the rainiest month in McMillin?
November, with 7.06 in of precipitation in a normal year; the driest is August with 0.90 in.
What plant hardiness zone is McMillin in?
The USDA's 2023 map puts McMillin in zone 8b in ZIP code 98374, the nearest ZIP area. By the same method at McMillin's NOAA station, the coldest night of a typical year reaches 18°F (21 years, 1991-2020): zone 8b.
How late can frost come in McMillin?
In half of years the last 32°F night comes after April 11; in one year in ten it comes after April 29. Waiting until April 29 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Washington climateThe statewide normals and every place in the state
- Tacoma #1, WA11 miles from this station, 53.7°F a year
- Buckley, WA12 miles from this station, 50.9°F a year
- Mud Mountain Dam, WA15 miles from this station, 49.9°F a year
- Tacoma, WA17 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