Climate averages 1991–2020
Kirkland weather
in September.
A mild, moderately wet month: the 3rd warmest and the joint 3rd driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Kirkland: daytime highs average 20.1°C and nights cool to about 11.0°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 71 mm of rain on roughly 9 days, which makes September a moderately wet month (the joint 3rd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 38 min on an average September day.
The nearest other city in this atlas is Bellevue (8 km away). In September its highs average 20.7°C, 0.6°C warmer than Kirkland, with 67 mm of rain.
Among the 498 cities listed in the United States, Kirkland ranks joint 493rd of 498 for the warmest September highs and joint 219th of 498 for the driest September (rainfall, lowest first). The mean September high of those 498 cities is 26.9°C; Kirkland is 6.8°C cooler than that mean.
From September to October, average highs fall by 5.7°C to 14.4°C, and monthly rainfall rises from 71 mm to 143 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Kirkland climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 7.1°C1.8°C | 1.8°C | 179 | 18.3 | 8.99 h |
| February | 8.5°C1.6°C | 1.6°C | 119 | 15.1 | 10.210 h |
| March | 10.6°C2.8°C | 2.8°C | 139 | 17.8 | 11.912 h |
| April | 13.2°C4.6°C | 4.6°C | 113 | 15.4 | 13.614 h |
| May | 16.8°C7.9°C | 7.9°C | 80 | 12.5 | 15.115 h |
| June | 19.2°C10.6°C | 10.6°C | 71 | 10.7 | 15.916 h |
| July | 23.1°C13.2°C | 13.2°C | 33 | 6.0 | 15.616 h |
| August | 23.4°C13.5°C | 13.5°C | 38 | 5.2 | 14.314 h |
| September, selected | 20.1°C11.0°C | 11.0°C | 71 | 8.7 | 12.613 h |
| October | 14.4°C7.3°C | 7.3°C | 143 | 14.6 | 10.911 h |
| November | 9.4°C4.0°C | 4.0°C | 198 | 18.1 | 9.49 h |
| December | 6.5°C1.8°C | 1.8°C | 181 | 17.9 | 8.59 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Bellevue in SeptemberUnited States · 8 kmHigh 20.7°C · Low 11.3°C · 67 mm rain
- Seattle in SeptemberUnited States · 12 kmHigh 20.6°C · Low 11.3°C · 67 mm rain
- Renton in SeptemberUnited States · 22 kmHigh 21.1°C · Low 11.6°C · 67 mm rain
- Everett in SeptemberUnited States · 33 kmHigh 19.9°C · Low 11.2°C · 83 mm rain
- Kent in SeptemberUnited States · 33 kmHigh 21.2°C · Low 11.8°C · 67 mm rain
- Federal Way in SeptemberUnited States · 41 kmHigh 20.3°C · Low 11.2°C · 64 mm rain
- Auburn in SeptemberUnited States · 42 kmHigh 20.8°C · Low 11.3°C · 64 mm rain
- Tacoma in SeptemberUnited States · 51 kmHigh 20.8°C · Low 11.9°C · 50 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Kirkland) is explained once on the Kirkland year overview and on the Sources, method and limits page.