Mountlake Terrace weather in September
In September, Mountlake Terrace sees average daytime highs of 66°F and overnight lows near 53°F, with 2.8 in of rain across 8.7 wet days and about 12.4 hours of daylight. It is the 3rd-warmest and 9th-wettest month of the year here.
Highs ease over the month, from about 69°F in the first days to 63°F by the end. The sky is clear or mostly clear about 42% of the time in September, and the air most often feels dry.
Daylight stretches from about 13 h 12 min at the start of September to 11 h 30 min by month's end. Set against the rest of the year, September is Mountlake Terrace's 3rd-clearest and 9th-windiest month. For the whole year in context, see Mountlake Terrace's year-round climate.
- Daytime high
- 66°
- 3rd warmest
- Overnight low
- 53°
- 10th coldest
- Rainfall
- 2.8 in
- 8.7 wet days
- Daylight
- 12 h 18 min
- 5:53 AM – 6:14 PM
- Cloud cover
- 47%
- 3rd clearest
- Wind
- 5 mph
- 9th windiest
- Solar energy
- 3.99 kWh/m²
- Travel score
- 6.5
- out of 10
Mountlake Terrace is city in Snohomish County, Washington, United States.
- Density
- 1,947/km²
- people per km²
- Founded
- 1954
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Temperature in September
Highs ease over the month, from about 69°F in the first days to 63°F by the end.
A typical September day in Mountlake Terrace reaches about 66°F in the afternoon and slips back to 53°F overnight — a 14°F spread between the day's warmth and the night's chill. On most days the high lands between 60°F and 74°F. Set against its neighbours, September runs about 6°F cooler than August and about 9°F warmer than October.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°F) | 70 | 69 | 69 | 69 | 69 | 69 | 69 | 68 | 68 | 68 | 68 | 67 | 67 | 67 | 67 | 66 | 66 | 66 | 66 | 65 | 65 | 65 | 65 | 65 | 64 | 64 | 64 | 63 | 63 | 63 |
| Avg low (°F) | 55 | 55 | 54 | 54 | 54 | 54 | 54 | 54 | 54 | 53 | 53 | 53 | 53 | 53 | 53 | 53 | 53 | 52 | 52 | 52 | 52 | 52 | 51 | 51 | 51 | 51 | 51 | 50 | 50 | 50 |
| Avg high (°F) | Avg low (°F) | |
|---|---|---|
| 1 | 70 | 55 |
| 2 | 69 | 55 |
| 3 | 69 | 54 |
| 4 | 69 | 54 |
| 5 | 69 | 54 |
| 6 | 69 | 54 |
| 7 | 69 | 54 |
| 8 | 68 | 54 |
| 9 | 68 | 54 |
| 10 | 68 | 53 |
| 11 | 68 | 53 |
| 12 | 67 | 53 |
| 13 | 67 | 53 |
| 14 | 67 | 53 |
| 15 | 67 | 53 |
| 16 | 66 | 53 |
| 17 | 66 | 53 |
| 18 | 66 | 52 |
| 19 | 66 | 52 |
| 20 | 65 | 52 |
| 21 | 65 | 52 |
| 22 | 65 | 52 |
| 23 | 65 | 51 |
| 24 | 65 | 51 |
| 25 | 64 | 51 |
| 26 | 64 | 51 |
| 27 | 64 | 51 |
| 28 | 63 | 50 |
| 29 | 63 | 50 |
| 30 | 63 | 50 |
Mountlake Terrace weather by month
How September compares with the rest of the year at a glance. September is the 3rd-warmest and 9th-wettest month here — the current month is highlighted below.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 46° / 39° | 7.1 | 18.3 | 2.1 | 8.6 | 0.9 |
| Feb | 48° / 39° | 4.7 | 14.9 | 1.8 | 9.9 | 1.5 |
| Mar | 51° / 41° | 5.5 | 17.8 | 0.8 | 11.6 | 2.1 |
| Apr | 56° / 44° | 4.4 | 15.4 | 0.1 | 13.4 | 3.2 |
| May | 62° / 48° | 3.1 | 12.5 | 0 | 14.9 | 4.9 |
| Jun | 66° / 52° | 2.8 | 10.7 | 0 | 15.7 | 5.9 |
| Jul | 71° / 56° | 1.3 | 6 | 0 | 15.4 | 7.6 |
| Aug | 72° / 56° | 1.5 | 5.2 | 0 | 14.1 | 7.7 |
| Sep | 66° / 53° | 2.8 | 8.7 | 0 | 12.4 | 6.5 |
| Oct | 58° / 47° | 5.6 | 14.6 | 0 | 10.6 | 3.8 |
| Nov | 50° / 42° | 7.8 | 18.1 | 0.6 | 9.1 | 1.7 |
| Dec | 45° / 38° | 7.1 | 17.9 | 2.1 | 8.3 | 0.8 |
Cloud cover in September
The sky is clear or mostly clear about 42% of the time in September.
Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 42%.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 61 | 62 | 63 | 63 | 63 | 62 | 62 | 62 | 61 | 61 | 60 | 60 | 59 | 59 | 58 | 58 | 57 | 57 | 57 | 56 | 56 | 55 | 55 | 55 | 55 | 55 | 55 | 54 | 54 | 52 |
| Cloudier (%) | 39 | 38 | 37 | 37 | 37 | 38 | 38 | 38 | 39 | 39 | 40 | 40 | 41 | 41 | 42 | 42 | 43 | 43 | 43 | 44 | 44 | 45 | 45 | 45 | 45 | 45 | 45 | 46 | 46 | 48 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| 1 | 61 | 39 |
| 2 | 62 | 38 |
| 3 | 63 | 37 |
| 4 | 63 | 37 |
| 5 | 63 | 37 |
| 6 | 62 | 38 |
| 7 | 62 | 38 |
| 8 | 62 | 38 |
| 9 | 61 | 39 |
| 10 | 61 | 39 |
| 11 | 60 | 40 |
| 12 | 60 | 40 |
| 13 | 59 | 41 |
| 14 | 59 | 41 |
| 15 | 58 | 42 |
| 16 | 58 | 42 |
| 17 | 57 | 43 |
| 18 | 57 | 43 |
| 19 | 57 | 43 |
| 20 | 56 | 44 |
| 21 | 56 | 44 |
| 22 | 55 | 45 |
| 23 | 55 | 45 |
| 24 | 55 | 45 |
| 25 | 55 | 45 |
| 26 | 55 | 45 |
| 27 | 55 | 45 |
| 28 | 54 | 46 |
| 29 | 54 | 46 |
| 30 | 52 | 48 |
Chance of precipitation in September
Mountlake Terrace gets around 2.8 in of rain over 8.7 wet days in September. The line is the day-by-day chance of measurable precipitation.
Day to day, the chance of measurable rain averages around 29% and peaks near 31% on the wettest days.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain chance (%) | 25 | 25 | 26 | 26 | 26 | 27 | 27 | 27 | 28 | 29 | 29 | 30 | 30 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 | 31 |
| Rain chance (%) | |
|---|---|
| 1 | 25 |
| 2 | 25 |
| 3 | 26 |
| 4 | 26 |
| 5 | 26 |
| 6 | 27 |
| 7 | 27 |
| 8 | 27 |
| 9 | 28 |
| 10 | 29 |
| 11 | 29 |
| 12 | 30 |
| 13 | 30 |
| 14 | 31 |
| 15 | 31 |
| 16 | 31 |
| 17 | 31 |
| 18 | 31 |
| 19 | 31 |
| 20 | 31 |
| 21 | 31 |
| 22 | 31 |
| 23 | 31 |
| 24 | 31 |
| 25 | 31 |
| 26 | 31 |
| 27 | 31 |
| 28 | 31 |
| 29 | 31 |
| 30 | 31 |
Humidity in September
Most of September feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
By dew point, September lands in the dry band about 82% of days. It rarely turns muggy — the humid and sticky bands barely register.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 74 | 73 | 74 | 75 | 75 | 76 | 76 | 77 | 78 | 78 | 79 | 79 | 80 | 80 | 82 | 82 | 83 | 83 | 84 | 85 | 85 | 86 | 87 | 88 | 89 | 89 | 90 | 91 | 91 | 92 |
| Comfortable (%) | 26 | 26 | 25 | 24 | 24 | 23 | 23 | 22 | 21 | 21 | 20 | 20 | 19 | 19 | 18 | 18 | 17 | 17 | 16 | 15 | 15 | 14 | 13 | 12 | 11 | 11 | 10 | 9 | 9 | 8 |
| Humid (%) | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Dry (%) | Comfortable (%) | Humid (%) | |
|---|---|---|---|
| 1 | 74 | 26 | 0 |
| 2 | 73 | 26 | 1 |
| 3 | 74 | 25 | 1 |
| 4 | 75 | 24 | 1 |
| 5 | 75 | 24 | 1 |
| 6 | 76 | 23 | 1 |
| 7 | 76 | 23 | 1 |
| 8 | 77 | 22 | 1 |
| 9 | 78 | 21 | 1 |
| 10 | 78 | 21 | 1 |
| 11 | 79 | 20 | 1 |
| 12 | 79 | 20 | 1 |
| 13 | 80 | 19 | 1 |
| 14 | 80 | 19 | 1 |
| 15 | 82 | 18 | 0 |
| 16 | 82 | 18 | 0 |
| 17 | 83 | 17 | 0 |
| 18 | 83 | 17 | 0 |
| 19 | 84 | 16 | 0 |
| 20 | 85 | 15 | 0 |
| 21 | 85 | 15 | 0 |
| 22 | 86 | 14 | 0 |
| 23 | 87 | 13 | 0 |
| 24 | 88 | 12 | 0 |
| 25 | 89 | 11 | 0 |
| 26 | 89 | 11 | 0 |
| 27 | 90 | 10 | 0 |
| 28 | 91 | 9 | 0 |
| 29 | 91 | 9 | 0 |
| 30 | 92 | 8 | 0 |
Wind in September
Winds average 5 mph in September.
Across September, daily wind ranges from about 5 mph on the calmest days to 5 mph at its breeziest. It stays fairly steady from day to day.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (mph) | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 5 |
| Feels | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm |
| Wind speed (mph) | Feels | |
|---|---|---|
| 1 | 5 | calm |
| 2 | 5 | calm |
| 3 | 5 | calm |
| 4 | 5 | calm |
| 5 | 5 | calm |
| 6 | 5 | calm |
| 7 | 5 | calm |
| 8 | 5 | calm |
| 9 | 5 | calm |
| 10 | 5 | calm |
| 11 | 5 | calm |
| 12 | 5 | calm |
| 13 | 5 | calm |
| 14 | 5 | calm |
| 15 | 5 | calm |
| 16 | 5 | calm |
| 17 | 5 | calm |
| 18 | 5 | calm |
| 19 | 5 | calm |
| 20 | 5 | calm |
| 21 | 5 | calm |
| 22 | 5 | calm |
| 23 | 5 | calm |
| 24 | 5 | calm |
| 25 | 5 | calm |
| 26 | 5 | calm |
| 27 | 5 | calm |
| 28 | 5 | calm |
| 29 | 5 | calm |
| 30 | 5 | calm |
Sunrise & sunset in September
Daylight runs from about 13 h 12 min at the start of September to 11 h 30 min by month's end. The lit band spans sunrise to sunset each day.
Days shrink by about 102 minutes over September. Sunrise moves from 5:32 AM to 6:13 AM, and sunset from 6:45 PM to 5:44 PM.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 13.2 | 13.2 | 13.1 | 13.0 | 13.0 | 12.9 | 12.9 | 12.8 | 12.8 | 12.7 | 12.6 | 12.6 | 12.5 | 12.5 | 12.4 | 12.3 | 12.3 | 12.2 | 12.2 | 12.1 | 12.0 | 12.0 | 11.9 | 11.9 | 11.8 | 11.7 | 11.7 | 11.6 | 11.6 | 11.5 |
| Sunrise (AM) | 5:32 | 5:34 | 5:35 | 5:37 | 5:38 | 5:39 | 5:41 | 5:42 | 5:44 | 5:45 | 5:46 | 5:48 | 5:49 | 5:51 | 5:52 | 5:53 | 5:55 | 5:56 | 5:58 | 5:59 | 6:00 | 6:02 | 6:03 | 6:05 | 6:06 | 6:07 | 6:09 | 6:10 | 6:12 | 6:13 |
| Sunset (PM) | 6:45 | 6:43 | 6:41 | 6:39 | 6:37 | 6:35 | 6:33 | 6:31 | 6:29 | 6:27 | 6:24 | 6:22 | 6:20 | 6:18 | 6:16 | 6:14 | 6:12 | 6:09 | 6:07 | 6:05 | 6:03 | 6:01 | 5:59 | 5:57 | 5:54 | 5:52 | 5:50 | 5:48 | 5:46 | 5:44 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| 1 | 13.2 | 5:32 | 6:45 |
| 2 | 13.2 | 5:34 | 6:43 |
| 3 | 13.1 | 5:35 | 6:41 |
| 4 | 13.0 | 5:37 | 6:39 |
| 5 | 13.0 | 5:38 | 6:37 |
| 6 | 12.9 | 5:39 | 6:35 |
| 7 | 12.9 | 5:41 | 6:33 |
| 8 | 12.8 | 5:42 | 6:31 |
| 9 | 12.8 | 5:44 | 6:29 |
| 10 | 12.7 | 5:45 | 6:27 |
| 11 | 12.6 | 5:46 | 6:24 |
| 12 | 12.6 | 5:48 | 6:22 |
| 13 | 12.5 | 5:49 | 6:20 |
| 14 | 12.5 | 5:51 | 6:18 |
| 15 | 12.4 | 5:52 | 6:16 |
| 16 | 12.3 | 5:53 | 6:14 |
| 17 | 12.3 | 5:55 | 6:12 |
| 18 | 12.2 | 5:56 | 6:09 |
| 19 | 12.2 | 5:58 | 6:07 |
| 20 | 12.1 | 5:59 | 6:05 |
| 21 | 12.0 | 6:00 | 6:03 |
| 22 | 12.0 | 6:02 | 6:01 |
| 23 | 11.9 | 6:03 | 5:59 |
| 24 | 11.9 | 6:05 | 5:57 |
| 25 | 11.8 | 6:06 | 5:54 |
| 26 | 11.7 | 6:07 | 5:52 |
| 27 | 11.7 | 6:09 | 5:50 |
| 28 | 11.6 | 6:10 | 5:48 |
| 29 | 11.6 | 6:12 | 5:46 |
| 30 | 11.5 | 6:13 | 5:44 |
Solar energy in September
Average shortwave solar energy reaching the ground each day in September, about 3.99 kWh/m².
For context, solar energy here swings from a low near 0.86 kWh/m² to a high of 6.07 kWh/m² in July across the year — September's 3.99 kWh/m² falls in the middle.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 4.7 | 4.6 | 4.6 | 4.5 | 4.5 | 4.5 | 4.4 | 4.4 | 4.3 | 4.3 | 4.2 | 4.1 | 4.1 | 4.0 | 4.0 | 3.9 | 3.9 | 3.8 | 3.8 | 3.7 | 3.6 | 3.6 | 3.5 | 3.5 | 3.5 | 3.4 | 3.3 | 3.3 | 3.2 | 3.2 |
| Level | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| 1 | 4.7 | Bright |
| 2 | 4.6 | Bright |
| 3 | 4.6 | Bright |
| 4 | 4.5 | Bright |
| 5 | 4.5 | Bright |
| 6 | 4.5 | Bright |
| 7 | 4.4 | Bright |
| 8 | 4.4 | Bright |
| 9 | 4.3 | Bright |
| 10 | 4.3 | Bright |
| 11 | 4.2 | Bright |
| 12 | 4.1 | Bright |
| 13 | 4.1 | Bright |
| 14 | 4.0 | Bright |
| 15 | 4.0 | Moderate |
| 16 | 3.9 | Moderate |
| 17 | 3.9 | Moderate |
| 18 | 3.8 | Moderate |
| 19 | 3.8 | Moderate |
| 20 | 3.7 | Moderate |
| 21 | 3.6 | Moderate |
| 22 | 3.6 | Moderate |
| 23 | 3.5 | Moderate |
| 24 | 3.5 | Moderate |
| 25 | 3.5 | Moderate |
| 26 | 3.4 | Moderate |
| 27 | 3.3 | Moderate |
| 28 | 3.3 | Moderate |
| 29 | 3.2 | Moderate |
| 30 | 3.2 | Moderate |
Hazard calendar for Mountlake Terrace
None of Mountlake Terrace's seasonal hazards are active in September. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.
Mountlake Terrace's rainy season runs October–April, when most of the year's rain falls.
Is September a good time to visit Mountlake Terrace?
Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).
September is a reasonable time to visit Mountlake Terrace for sightseeing.
What to pack for Mountlake Terrace in September
From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In September, Mountlake Terrace sees daytime highs around 66°F and nights near 53°F. Worth packing: rain gear. About 9 days see rain.
Sea temperature near Mountlake Terrace in September
The nearest coast averages about 53°F in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 35 mi away) is warmest in August at about 53°F and coldest in February near 46°F.
The water stays below 68°F all year — cool enough that most swimmers want a wetsuit.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°F) | 46 | 46 | 47 | 48 | 50 | 52 | 53 | 53 | 53 | 50 | 49 | 47 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing | Bracing |
| Sea temperature (°F) | Comfort | |
|---|---|---|
| Jan | 46 | Bracing |
| Feb | 46 | Bracing |
| Mar | 47 | Bracing |
| Apr | 48 | Bracing |
| May | 50 | Bracing |
| Jun | 52 | Bracing |
| Jul | 53 | Bracing |
| Aug | 53 | Bracing |
| Sep | 53 | Bracing |
| Oct | 50 | Bracing |
| Nov | 49 | Bracing |
| Dec | 47 | Bracing |
UV index in Mountlake Terrace in September
Clear-sky midday UV in September peaks around 4 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Mountlake Terrace peaks around July 17 at about 8 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near December 18 at about 1 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 7 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 1 | 1 | 4 | 5 | 7 | 6 | 8 | 6 | 4 | 3 | 1 | 1 |
| Level | Low | Low | Moderate | Moderate | High | High | Very high | High | Moderate | Moderate | Low | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 1 | Low |
| Feb | 1 | Low |
| Mar | 4 | Moderate |
| Apr | 5 | Moderate |
| May | 7 | High |
| Jun | 6 | High |
| Jul | 8 | Very high |
| Aug | 6 | High |
| Sep | 4 | Moderate |
| Oct | 3 | Moderate |
| Nov | 1 | Low |
| Dec | 1 | Low |
Air quality in Mountlake Terrace in September
Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.
Air quality in Mountlake Terrace is worst in August — around 20 µg/m³ PM2.5 (moderate), about 3.1× the cleanest month (December, 6 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 8 | 10 | 12 | 12 | 13 | 11 | 10 | 20 | 18 | 11 | 7 | 6 |
| Level | Good | Good | Moderate | Good | Moderate | Good | Good | Moderate | Moderate | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 8 | Good |
| Feb | 10 | Good |
| Mar | 12 | Moderate |
| Apr | 12 | Good |
| May | 13 | Moderate |
| Jun | 11 | Good |
| Jul | 10 | Good |
| Aug | 20 | Moderate |
| Sep | 18 | Moderate |
| Oct | 11 | Good |
| Nov | 7 | Good |
| Dec | 6 | Good |
Where is Mountlake Terrace?
Mountlake Terrace sits at 47.8°N, 122.3°W, 459 ft above sea level, in United States. The nearest listed city is Lynnwood, 2.5 mi away.
Topography around Mountlake Terrace
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Mountlake Terrace.
Within 2 miles, the terrain around Mountlake Terrace has only modest variations in elevation — a maximum elevation change of 430 ft around an average of 387 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 712 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 7,589 ft.
The land around Mountlake Terrace is covered by trees (62%) and artificial surfaces (31%) within 2 miles, trees (44%) and water (34%) within 10 miles, and trees (69%) within 50 miles.
United States travel facts
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 100% of US
- price level, 2025
- GDP per capita
- $90,027
- 2025
- Happiness
- 6.8 / 10
- World Happiness, 2025
- Safe drinking water
- 98%
- of population, 2024
- Homicide rate
- 5.8
- per 100k, 2023
- Road deaths
- 12.7
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Mountlake Terrace (47.7882°, -122.3087°, elevation 459 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).