American Falls, ID

Idaho · Records since 1892–2025

☀️ 75°F Feels like 68°
Currently in American Falls
As of 12:00 PM MDT

Records for September 11

🔥 Record High

97°F

September 11, 1899

+18° from 79° normal

❄ Record Low

30°F

September 11, 1916

-18° from 48° normal
🌞 Normal high: 79°F 🌑 Normal low: 48°F 1991–2020 normals

All-Time Records — American Falls

🔥
106°F
Hottest Day Ever
Jul 14, 1925
❄
-38°F
Coldest Day Ever
Jan 25, 1949
🌧
2.16"
Wettest Day Ever
Jun 10, 2024
☃
17.0"
Most Snow in One Day
Jan 26, 1897

First & Last Dates — American Falls

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)
192 days
Longest growing season
1992
4 days
Shortest growing season
1911
141 days
Normal growing season
1991–2020 average

Top 10 Record Highs — September 11

# Temp Date
🏆 97°F September 11, 1899
2 95°F September 11, 1990
3 95°F September 11, 1923
4 92°F September 11, 1963
5 92°F September 11, 1919
6 90°F September 11, 1959
7 89°F September 11, 1971
8 88°F September 11, 1981
9 88°F September 11, 1958
10 88°F September 11, 1946

Top 5 Record Lows — September 11

# Temp Date
🥶 30°F September 11, 1916
2 32°F September 11, 1912
3 33°F September 11, 1911
4 33°F September 11, 1904
5 34°F September 11, 1924
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 1892–2025. Climate normals represent the 1991–2020 average.

Heat Wave Summary — American Falls

threshold: 95°F (90th percentile of historical Jun–Aug highs)
4.5
Avg heat wave length
days (historical)
99°
Avg peak temp
during heat waves
0
Dangerous nights 2026
Overnights ≥ 70°F
0
Heat waves 2026
so far

Days ≥ 90°F Per Year

1893–2026
0
2026 so far
31
Avg/year 1970–2025
40
Avg/year (last 10 complete)
69
Most in a year (1919)

Average Daily High by Decade

Full year · complete decades only

Longest Heat Waves — American Falls

# Dates Days Peak Avg High Avg Overnight Low
🏆 Aug 3, 1915 – Aug 21, 1915 19 99°F (Aug 5) 97°F 50°F
2 Jul 1, 1917 – Jul 17, 1917 17 102°F (Jul 8) 98°F 46°F
3 Jul 15, 1901 – Jul 26, 1901 12 103°F (Jul 22) 98°F 54°F
4 Jun 19, 1919 – Jun 28, 1919 10 101°F (Jun 25) 98°F 44°F
5 Jul 18, 2013 – Jul 27, 2013 10 100°F (Jul 19) 97°F 59°F
6 Jul 2, 2017 – Jul 10, 2017 9 103°F (Jul 6) 99°F 59°F
7 Jul 12, 1925 – Jul 19, 1925 8 106°F (Jul 14) 102°F 61°F
8 Jun 8, 1918 – Jun 15, 1918 8 103°F (Jun 13) 99°F 57°F
9 Jun 27, 2013 – Jul 4, 2013 8 101°F (Jun 29) 99°F 62°F
10 Jun 27, 2015 – Jul 4, 2015 8 99°F (Jun 27) 98°F 63°F

Heat Waves Per Year

Warm Summer Nights (Jun–Aug)

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

0
2026 total
above-normal nights
35.9
Avg / summer
1970–2020
70
Most in a summer
2021

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 (1892–2026)

Blue = above average · tan = below average · gold = 2026 (partial)

Heavy Rain Days Per Year (≥ 1.0")

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

This Year — 2026

How American Falls is tracking against normal, year to date

Daily High Temperature vs Normal

Above normal Below normal

0 of 0 days with data were above the 1991–2020 normal high for their date.

Precipitation, Year to Date

0.00"
2026 YTD
Normal: 7.89"
-7.89"
0.00"
September so far
September normal: 0.81"
-0.81"
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 · American Falls is 7.89" 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)
2026 is still under way for this window — totals and rankings appear once September 10 passes.

Average Temperature by Year — Aug 11 – Sep 10

1893–2025 · 2026 highlighted · trend +0.31° per decade (warming since 1893)

Precipitation by Year — Aug 11 – Sep 10

1893–2025 · 2026 highlighted · trend +0.01" per decade (wetter since 1893)

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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