DeKalb in Fall
In fall (September, October and November), DeKalb sees average daytime highs around 60°F and overnight lows near 43°F, with 8.8 in of precipitation over about 25 wet days across the season. It is the 2nd-warmest season and the 3rd-wettest season.
Over the season highs ease from about 78°F in early September to 41°F by late November. The sky is clear or mostly clear about 34% of the time across fall, and the air most often feels dry.
Fall is DeKalb's 2nd-best season to visit on our travel score. For the whole year in context, see DeKalb's year-round climate.
- Avg daytime high
- 60°F
- 2nd-warmest season
- Avg overnight low
- 43°F
- Precipitation
- 8.8 in
- 25 wet days
- Avg wind
- 9 mph
- Travel score
- 4.6
- 2nd-best season
- Months
- Sep · Oct · Nov
Temperature in DeKalb in Fall
Over the season highs ease from about 78°F in early September to 41°F by late November.
A typical fall day in DeKalb reaches about 60°F and drops to 43°F overnight. The warmest of the three months is September, the coolest November.
How fall really feels in DeKalb
Once humidity and wind are folded in, fall brings about 0 days that feel above 90°F and 33 that feel at or below 32°F.
The story in fall is cold — wind chill drags the overnight "feels like" below the raw low.
DeKalb weather by month
How the three fall months (September, October and November) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 29° / 16° | 2.0 | 7.6 | 5.7 | 9.3 | 0.0 |
| Feb | 34° / 19° | 1.8 | 6.9 | 4.9 | 10.3 | 0.0 |
| Mar | 46° / 29° | 2.6 | 9.3 | 2.9 | 11.7 | 1.3 |
| Apr | 59° / 40° | 4.4 | 12 | 0.9 | 13.1 | 4.1 |
| May | 69° / 50° | 4.8 | 12.8 | 0 | 14.3 | 5.9 |
| Jun | 78° / 60° | 4.2 | 12.2 | 0 | 15 | 6.3 |
| Jul | 82° / 64° | 3.5 | 10.7 | 0 | 14.7 | 6.4 |
| Aug | 80° / 62° | 3.5 | 10.4 | 0 | 13.7 | 6.6 |
| Sep | 74° / 54° | 3.2 | 8.7 | 0 | 12.3 | 7.0 |
| Oct | 61° / 43° | 3.1 | 9.1 | 0.1 | 10.9 | 5.2 |
| Nov | 47° / 32° | 2.4 | 7.7 | 1.6 | 9.6 | 1.5 |
| Dec | 35° / 22° | 2.2 | 7.8 | 4.5 | 9 | 0.0 |
Cloud cover in Fall
The sky is clear or mostly clear about 34% of the time across fall.
Chance of precipitation in Fall
DeKalb gets around 8.8 in of rain and snow over 25 wet days across fall. The line is the day-by-day chance of measurable precipitation.
Humidity in Fall
Most of fall feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Fall
Winds average 9 mph across fall.
Sunrise & sunset in Fall
Daylight runs from about 13 hours in early September to 9 h 12 min by late November. The lit band spans sunrise to sunset each day.
Solar energy in Fall
Average shortwave solar energy reaching the ground each day across fall, about 3.2 kWh/m².
Is fall a good time to visit DeKalb?
Our two travel scores rate fall for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
fall is a reasonable time to visit DeKalb for sightseeing.
What to pack for DeKalb in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, DeKalb sees daytime highs around 60°F and nights near 43°F. Pack a warm layer. Worth having: light clothes and rain gear. About 25 days see rain.
UV index in DeKalb in Fall
Clear-sky midday UV across fall averages 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 DeKalb peaks around June 19 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 2 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 2 | 3 | 4 | 6 | 8 | 9 | 8 | 8 | 6 | 3 | 2 | 2 |
| Level | Low | Moderate | Moderate | High | Very high | Very high | Very high | Very high | High | Moderate | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 2 | Low |
| Feb | 3 | Moderate |
| Mar | 4 | Moderate |
| Apr | 6 | High |
| May | 8 | Very high |
| Jun | 9 | Very high |
| Jul | 8 | Very high |
| Aug | 8 | Very high |
| Sep | 6 | High |
| Oct | 3 | Moderate |
| Nov | 2 | Moderate |
| Dec | 2 | Low |
Air quality in DeKalb in Fall
Average fine-particle pollution (PM2.5) through the year — so you can see where fall falls, not just the annual average.
Air quality in DeKalb is worst in July — around 17 µg/m³ PM2.5 (moderate), about 1.9× the cleanest month (October, 9 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) | 12 | 15 | 16 | 14 | 15 | 16 | 17 | 16 | 13 | 9 | 10 | 11 |
| Level | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 12 | Moderate |
| Feb | 15 | Moderate |
| Mar | 16 | Moderate |
| Apr | 14 | Moderate |
| May | 15 | Moderate |
| Jun | 16 | Moderate |
| Jul | 17 | Moderate |
| Aug | 16 | Moderate |
| Sep | 13 | Moderate |
| Oct | 9 | Good |
| Nov | 10 | Good |
| Dec | 11 | Good |
Where is DeKalb?
DeKalb sits at 41.9°N, 88.8°W, 879 ft above sea level, in United States. The nearest listed city is Sycamore, 5.0 mi away.
Topography around DeKalb
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of DeKalb.
Within 2 miles, the terrain around DeKalb has only modest variations in elevation — a maximum elevation change of 102 ft around an average of 883 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 308 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 850 ft.
The land around DeKalb is covered by artificial surfaces (35%), trees (23%) and grassland (23%) within 2 miles, cropland (84%) within 10 miles, and cropland (59%) 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 DeKalb (41.9295°, -88.7504°, elevation 879 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.