Sunshine hours in Tri-Cities: 2,450 hours a year, month by month

Tri-Cities gets 2,450 hours of sunshine a year on average (6.7 a day). Sunniest month: July with 385 hours. Every month, measured 1961–1987.

• Tri-Cities gets 2,450 hours of sunshine a year on average, 6.7 a day – 55% of the astronomically possible. The sunniest month is July with 385 hours (12.4 a day), the dullest December with 40 (1.3 a day).
• Number 278 of 311 large cities in the United States.
• Nearest weather station: Walla Walla/City-County Arpt WA, 71 km away – 1961–1987 average, NOAA.

Sunshine hours month by month

• January: 51 h · 1.6 h a day · 18 %
• February: 83 h · 3.0 h a day · 29 %
• March: 174 h · 5.6 h a day · 47 %
• April: 222 h · 7.4 h a day · 55 %
• May: 289 h · 9.3 h a day · 62 %
• June: 326 h · 10.9 h a day · 69 %
• July: 385 h · 12.4 h a day · 81 %
• August: 344 h · 11.1 h a day · 79 %
• September: 269 h · 9.0 h a day · 71 %
• October: 199 h · 6.4 h a day · 59 %
• November: 68 h · 2.3 h a day · 24 %
• December: 40 h · 1.3 h a day · 15 %

Questions about sunshine hours

• How many hours of sunshine does Tri-Cities get a year? On average over 1961–1987 the sun shines in Tri-Cities for 2,450 hours a year – 6.7 hours a day and 55% of the time the sun is above the horizon.
• What is the sunniest month in Tri-Cities? July, with 385 hours of sunshine, 12.4 a day on average. The least sun comes in December: 40 hours, 1.3 a day.
• Is Tri-Cities a sunny city? Among the 311 large cities in the United States with measurements, Tri-Cities ranks number 278.
• Where do the figures come from? From the WMO climate normals 1961–1990 as archived by NOAA. There are no newer figures: the US stopped measuring sunshine duration in the 1990s. Tri-Cities uses the station Walla Walla/City-County Arpt WA, measured 1961–1987.
• What counts as an hour of sunshine? By the World Meteorological Organization's definition the sun is shining once its direct radiation exceeds 120 watts per square metre. Just after sunrise and before sunset it is often too weak – which is why even deserts never reach 100%.

The sunniest large cities: United States

• 1. Phoenix: 3,873 h a year
• 2. Las Vegas: 3,826 h a year
• 3. Tucson: 3,806 h a year
• 4. Reno: 3,647 h a year
• 5. Sacramento: 3,609 h a year
• 6. Fresno: 3,565 h a year
• 7. Chico: 3,542 h a year
• 8. Colorado Springs: 3,463 h a year
• 9. Albuquerque: 3,414 h a year
• 10. Amarillo: 3,298 h a year

The cloudiest large cities: United States

• 1. Pittsburgh: 1,972 h a year
• 2. Anchorage: 2,063 h a year
• 3. Syracuse: 2,120 h a year
• 4. Seattle: 2,170 h a year
• 5. Columbus: 2,182 h a year
• 6. Grand Rapids: 2,188 h a year
• 7. Buffalo: 2,206 h a year
• 8. Meads: 2,259 h a year
• 9. Cleveland: 2,281 h a year
• 10. Rochester: 2,299 h a year

The sunniest large cities in the world

• 1. Mexicali: 4,017 h a year
• 2. Phoenix: 3,873 h a year
• 3. Las Vegas: 3,826 h a year
• 4. Tucson: 3,806 h a year
• 5. Ciudad Juárez: 3,763 h a year
• 6. Reno: 3,647 h a year
• 7. Dubai: 3,610 h a year
• 8. Sacramento: 3,609 h a year
• 9. Victoria de Durango: 3,573 h a year
• 10. Fresno: 3,565 h a year

The cloudiest large cities in the world

• 1. Chengdu: 962 h a year
• 2. Chongqing: 985 h a year
• 3. Sukabumi: 1,082 h a year
• 4. Glasgow: 1,153 h a year
• 5. Tanjung Pinang: 1,172 h a year
• 6. Medan: 1,201 h a year
• 7. Samarinda: 1,275 h a year
• 8. Sungai Penuh: 1,311 h a year
• 9. Limerick: 1,339 h a year
• 10. Huaihua: 1,352 h a year

• Data: NOAA, WMO climate normals of sunshine duration, 1961–1987 average, public domain. Possible hours: time between sunrise and sunset.