Rosemont in Fall
In fall (September, October and November), Rosemont sees average daytime highs around 77°F and overnight lows near 52°F, with 4.1 in of rain over about 11 wet days across the season. It is the 2nd-warmest season and the 3rd-wettest season.
Over the season highs ease from about 90°F in early September to 60°F by late November. The sky is clear or mostly clear about 67% of the time across fall, and the air most often feels dry.
Fall is Rosemont's 2nd-best season to visit on our travel score. For the whole year in context, see Rosemont's year-round climate.
- Avg daytime high
- 77°F
- 2nd-warmest season
- Avg overnight low
- 52°F
- Rainfall
- 4.1 in
- 11 wet days
- Avg wind
- 4 mph
- Travel score
- 7.1
- 2nd-best season
- Months
- Sep · Oct · Nov
Temperature in Rosemont in Fall
Over the season highs ease from about 90°F in early September to 60°F by late November.
A typical fall day in Rosemont reaches about 77°F and drops to 52°F overnight. The warmest of the three months is September, the coolest November.
How fall really feels in Rosemont
Once humidity and wind are folded in, fall brings about 3 days that feel above 90°F and 0 that feel at or below 32°F.
The story in fall is heat — humidity pushes the afternoon "feels like" well above the raw temperature.
Rosemont 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 | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 57° / 41° | 4.9 | 9.5 | 9.6 | 4.2 |
| Feb | 62° / 43° | 4.7 | 9.6 | 10.5 | 5.2 |
| Mar | 66° / 46° | 4.1 | 9.2 | 11.7 | 6.3 |
| Apr | 72° / 50° | 1.9 | 5.8 | 13 | 7.5 |
| May | 80° / 55° | 1.1 | 4 | 14.1 | 7.7 |
| Jun | 88° / 59° | 0.2 | 1 | 14.6 | 5.9 |
| Jul | 91° / 62° | 0.0 | 0.1 | 14.4 | 4.8 |
| Aug | 91° / 61° | 0.1 | 0.2 | 13.5 | 5.0 |
| Sep | 87° / 59° | 0.1 | 0.7 | 12.3 | 6.4 |
| Oct | 78° / 53° | 1.4 | 3.2 | 11 | 8.3 |
| Nov | 65° / 45° | 2.6 | 6.6 | 9.9 | 6.5 |
| Dec | 57° / 40° | 4.8 | 9.7 | 9.4 | 4.1 |
Cloud cover in Fall
The sky is clear or mostly clear about 67% of the time across fall.
Chance of precipitation in Fall
Rosemont gets around 4.1 in of rain over 11 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 4 mph across fall.
Sunrise & sunset in Fall
Daylight runs from about 12 h 54 min in early September to 9 h 30 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 4.3 kWh/m².
Hazard calendar for Rosemont
In fall, Rosemont overlaps its rainy season season. The full year is below, with each hazard's peak months called out.
Rosemont's rainy season runs November–March, when most of the year's rain falls.
Is fall a good time to visit Rosemont?
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 one of the better times to visit Rosemont for general sightseeing. The water and warmth also suit a beach or pool day.
What to pack for Rosemont in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, Rosemont sees daytime highs around 77°F and nights near 52°F. Pack light clothes and sun protection. Worth having: a warm layer. About 11 days see rain.
UV index in Rosemont 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 Rosemont peaks around June 21 at about 10 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 14 at about 2 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 2 | 3 | 4 | 6 | 8 | 10 | 10 | 9 | 6 | 5 | 2 | 2 |
| Level | Moderate | Moderate | Moderate | High | Very high | Very high | Very high | Very high | High | Moderate | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 2 | Moderate |
| Feb | 3 | Moderate |
| Mar | 4 | Moderate |
| Apr | 6 | High |
| May | 8 | Very high |
| Jun | 10 | Very high |
| Jul | 10 | Very high |
| Aug | 9 | Very high |
| Sep | 6 | High |
| Oct | 5 | Moderate |
| Nov | 2 | Moderate |
| Dec | 2 | Low |
Air quality in Rosemont 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 Rosemont is worst in August — around 27 µg/m³ PM2.5 (moderate), about 3.6× the cleanest month (June, 8 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) | 15 | 14 | 15 | 12 | 9 | 8 | 11 | 27 | 23 | 17 | 19 | 14 |
| Level | Moderate | Moderate | Moderate | Good | Good | Good | Good | Moderate | Moderate | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 15 | Moderate |
| Feb | 14 | Moderate |
| Mar | 15 | Moderate |
| Apr | 12 | Good |
| May | 9 | Good |
| Jun | 8 | Good |
| Jul | 11 | Good |
| Aug | 27 | Moderate |
| Sep | 23 | Moderate |
| Oct | 17 | Moderate |
| Nov | 19 | Moderate |
| Dec | 14 | Moderate |
Where is Rosemont?
Rosemont sits at 38.6°N, 121.4°W, 49 ft above sea level, in United States. The nearest listed city is Arden-Arcade, 3.7 mi away.
Topography around Rosemont
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Rosemont.
Within 2 miles, the terrain around Rosemont has only modest variations in elevation — a maximum elevation change of 108 ft around an average of 52 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 328 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 5,384 ft.
The land around Rosemont is covered by artificial surfaces (51%) and trees (20%) within 2 miles, artificial surfaces (43%), grassland (28%) and trees (20%) within 10 miles, and trees (34%), grassland (31%) and cropland (23%) 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 Rosemont (38.5519°, -121.3647°, elevation 49 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.