Tri-Cities, WA

Washington · Records since 1894–2026

☁️ 74°F
Currently in Tri-Cities
As of 11:30 AM PDT

Records for September 11

🔥 Record High

98°F

September 11, 1973

+15° from 83° normal

❄ Record Low

37°F

September 11, 2012

-12° from 49° normal
🌞 Normal high: 83°F 🌑 Normal low: 49°F 1991–2020 normals

All-Time Records — Tri-Cities

🔥
115°F
Hottest Day Ever
Jun 27, 2021
❄
-29°F
Coldest Day Ever
Dec 13, 1919
🌧
2.00"
Wettest Day Ever
Nov 20, 1921
☃
14.0"
Most Snow in One Day
Nov 20, 1921

First & Last Dates — Tri-Cities

How early and how late each seasonal turning point has ever arrived, across the full period of record

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Range ever recorded Normal date (1991–2020)
237 days
Longest growing season
1993
123 days
Shortest growing season
1921
174 days
Normal growing season
1991–2020 average

Top 10 Record Highs — September 11

# Temp Date
🏆 98°F September 11, 1973
2 97°F September 11, 1944
3 95°F September 11, 1943
4 95°F September 11, 1940
5 95°F September 11, 1908
6 94°F September 11, 2013
7 94°F September 11, 1990
8 94°F September 11, 1953
9 94°F September 11, 1899
10 93°F September 11, 2011

Top 5 Record Lows — September 11

# Temp Date
🥶 37°F September 11, 2012
2 38°F September 11, 1915
3 38°F September 11, 1910
4 39°F September 11, 1904
5 40°F September 11, 2014
About this data — Records are sourced from the NOAA Threadex dataset via RCC ACIS, a quality-controlled record for long-term climate stations. Threadex adjusts for station relocations and observation-time changes, making records comparable across all years since 1894–2026. Climate normals represent the 1991–2020 average.

Heat Wave Summary — Tri-Cities

threshold: 99°F (90th percentile of historical Jun–Aug highs)
4.7
Avg heat wave length
days (historical)
105°
Avg peak temp
during heat waves
2
Dangerous nights 2026
Overnights ≥ 70°F
2
Heat waves 2026
so far

Days ≥ 90°F Per Year

1894–2026
60
2026 so far
49
Avg/year 1970–2025
62
Avg/year (last 10 complete)
77
Most in a year (1940)

Average Daily High by Decade

Full year · complete decades only

Longest Heat Waves — Tri-Cities

# Dates Days Peak Avg High Avg Overnight Low
🏆 Jul 5, 2024 – Jul 21, 2024 17 109°F (Jul 9) 103°F 60°F
2 Jul 24, 2022 – Aug 3, 2022 11 112°F (Jul 29) 105°F 62°F
3 Aug 11, 1977 – Aug 21, 1977 11 110°F (Aug 17) 104°F 66°F
4 Jul 13, 1938 – Jul 23, 1938 11 109°F (Jul 21) 104°F 65°F
5 Jul 11, 1906 – Jul 21, 1906 11 108°F (Jul 12) 103°F 72°F
6 Aug 10, 1967 – Aug 20, 1967 11 105°F (Aug 17) 102°F 61°F
7 Aug 7, 1981 – Aug 16, 1981 10 105°F (Aug 9) 102°F 64°F
8 Jul 22, 1939 – Jul 30, 1939 9 115°F (Jul 27) 105°F 65°F
9 Jun 23, 2021 – Jul 1, 2021 9 115°F (Jun 27) 107°F 68°F
10 Jul 12, 1911 – Jul 20, 1911 9 114°F (Jul 16) 107°F 68°F

Heat Waves Per Year

Warm Summer Nights (Jun–Aug)

Nights where the overnight low exceeded the 1991–2020 normal low

44
2026 total
above-normal nights
51.4
Avg / summer
1970–2020
81
Most in a summer
1997

Above-Normal Summer Nights Per Year

Average June–August Low by Decade

Overnight lows · complete decades only

Precipitation

Annual totals and trend across the full period of record · see this year's standing →

Monthly Precipitation — Last 24 Months

Blue = actual · dashed line = monthly normal

Annual Precipitation Per Year (1894–2026)

Blue = above average · tan = below average · gold = 2026 (partial)
Since 1894, annual totals have trended +0.11" per decade, about +1.4" across the record.

Heavy Rain Days Per Year (≥ 1.0")

Compare year-to-year changes in days with heavy rainfall (≥ 1.0")

This Year — 2026

How Tri-Cities is tracking against normal, year to date

Daily High Temperature vs Normal

Above normal Below normal

138 of 253 days with data were above the 1991–2020 normal high for their date.

Precipitation, Year to Date

3.65"
2026 YTD
Normal: 4.83"
-1.18"
0.05"
September so far
September normal: 0.31"
-0.26"
0
2026 heavy rain days
Days with ≥ 1.0"

Accumulation vs. Normal

Running total since Jan 1 against the normal pace for the same date · Tri-Cities is 1.18" behind the normal pace

Period Review — Aug 11 – Sep 10, 2026

Any window, evaluated against every other year on record — 31 days

Quick picks: Last 7 days Last 30 days Last 90 days This month
Seasons: Spring (Mar–May) Summer (Jun–Aug) Fall (Sep–Nov)
71.4°F
Average temperature
55th-warmest of 124
+0.3°
vs. average
Normal: 71.1°F (1991–2020)

Average Temperature by Year — Aug 11 – Sep 10

1894–2026 · 2026 highlighted · trend +0.15° per decade (warming since 1894)

Precipitation by Year — Aug 11 – Sep 10

1895–2025 · 2026 highlighted · trend -0.01" per decade (drier since 1895)

Warmest Aug 11 – Sep 10 on Record

# Year Avg Temp
1 1967 77.9°F
2 2022 77.9°F
3 1934 76.1°F
4 2025 75.9°F
5 1986 75.7°F
6 1894 75.2°F
7 1997 74.5°F
8 1961 74.2°F
9 1991 74.1°F
10 2013 74.1°F

Coolest Aug 11 – Sep 10 on Record

# Year Avg Temp
1 1910 65.4°F
2 1899 66.1°F
3 2000 66.3°F
4 1895 66.8°F
5 1959 66.9°F
6 1960 67.3°F
7 1937 67.3°F
8 1912 67.4°F
9 1964 67.5°F
10 1920 67.5°F
About this data. Pick any start and end date and this becomes the same kind of review as the Month and Fall tabs, just for exactly the window you asked for — the generalized version of the same engine, evaluated across every year on record. Average temperature is the mean of each day's (high + low) / 2; precipitation is the sum of daily totals. A year missing more than about a fifth of the window's days is excluded from the temperature ranking; any missing day excludes a year from the precipitation ranking, since an unreported day is unreported rain. Ranges that cross from December into January aren't supported yet. Normals are the 1991–2020 mean for the same window.
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