Casa de Oro-Mount Helix in Fall
In fall (September, October and November), Casa de Oro-Mount Helix sees average daytime highs around 75°F and overnight lows near 59°F, with 1.7 in of rain over about 7 wet days across the season. It is the 2nd-warmest season and the 3rd-wettest season.
Over the season highs ease from about 81°F in early September to 67°F by late November. The sky is clear or mostly clear about 71% of the time across fall, and the air most often feels dry.
Fall is Casa de Oro-Mount Helix's 2nd-best season to visit on our travel score. For the whole year in context, see Casa de Oro-Mount Helix's year-round climate.
- Avg daytime high
- 75°F
- 2nd-warmest season
- Avg overnight low
- 59°F
- Rainfall
- 1.7 in
- 7 wet days
- Avg wind
- 4 mph
- Travel score
- 8.5
- 2nd-best season
- Months
- Sep · Oct · Nov
Temperature in Casa de Oro-Mount Helix in Fall
Over the season highs ease from about 81°F in early September to 67°F by late November.
A typical fall day in Casa de Oro-Mount Helix reaches about 75°F and drops to 59°F overnight. The warmest of the three months is September, the coolest November.
Casa de Oro-Mount Helix 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 | 64° / 48° | 2.3 | 5.6 | 10.1 | 6.8 |
| Feb | 64° / 48° | 2.9 | 7 | 10.8 | 6.3 |
| Mar | 65° / 50° | 1.9 | 5.8 | 11.8 | 6.8 |
| Apr | 68° / 53° | 0.9 | 3.9 | 12.8 | 7.6 |
| May | 70° / 56° | 0.4 | 2 | 13.7 | 8.2 |
| Jun | 74° / 60° | 0.1 | 0.6 | 14.1 | 9.2 |
| Jul | 79° / 64° | 0.1 | 0.7 | 13.9 | 8.9 |
| Aug | 81° / 65° | 0.1 | 0.5 | 13.2 | 8.7 |
| Sep | 80° / 64° | 0.2 | 0.9 | 12.2 | 8.8 |
| Oct | 76° / 59° | 0.6 | 2.5 | 11.2 | 8.7 |
| Nov | 70° / 53° | 0.9 | 3.3 | 10.3 | 7.9 |
| Dec | 64° / 48° | 1.9 | 5.2 | 9.9 | 6.8 |
Cloud cover in Fall
The sky is clear or mostly clear about 71% of the time across fall.
Chance of precipitation in Fall
Casa de Oro-Mount Helix gets around 1.7 in of rain over 7 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 42 min in early September to 10 hours 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 4.9 kWh/m².
Is fall a good time to visit Casa de Oro-Mount Helix?
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 Casa de Oro-Mount Helix for general sightseeing. The water and warmth also suit a beach or pool day.
What to pack for Casa de Oro-Mount Helix in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, Casa de Oro-Mount Helix sees daytime highs around 75°F and nights near 59°F. Pack sun protection. Worth having: light clothes. About 7 days see rain.
Sea temperature near Casa de Oro-Mount Helix in Fall
The nearest coast averages about 66°F across fall — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 13 mi away) is warmest in August at about 70°F and coldest in February near 59°F.
It's comfortable for a long swim from Jul 13 to Sep 28 — about 2.6 months when the water holds above 68°F.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°F) | 60 | 59 | 60 | 61 | 63 | 65 | 68 | 70 | 69 | 67 | 64 | 61 |
| Comfort | Cool | Cool | Cool | Cool | Cool | Cool | Refreshing | Refreshing | Refreshing | Cool | Cool | Cool |
| Sea temperature (°F) | Comfort | |
|---|---|---|
| Jan | 60 | Cool |
| Feb | 59 | Cool |
| Mar | 60 | Cool |
| Apr | 61 | Cool |
| May | 63 | Cool |
| Jun | 65 | Cool |
| Jul | 68 | Refreshing |
| Aug | 70 | Refreshing |
| Sep | 69 | Refreshing |
| Oct | 67 | Cool |
| Nov | 64 | Cool |
| Dec | 61 | Cool |
UV index in Casa de Oro-Mount Helix in Fall
Clear-sky midday UV across fall averages around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Casa de Oro-Mount Helix peaks around June 22 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 at about 3 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 4 | 5 | 5 | 8 | 8 | 11 | 11 | 11 | 9 | 6 | 4 | 3 |
| Level | Moderate | Moderate | High | Very high | Very high | Extreme | Extreme | Extreme | Very high | High | Moderate | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 4 | Moderate |
| Feb | 5 | Moderate |
| Mar | 5 | High |
| Apr | 8 | Very high |
| May | 8 | Very high |
| Jun | 11 | Extreme |
| Jul | 11 | Extreme |
| Aug | 11 | Extreme |
| Sep | 9 | Very high |
| Oct | 6 | High |
| Nov | 4 | Moderate |
| Dec | 3 | Moderate |
Air quality in Casa de Oro-Mount Helix 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 Casa de Oro-Mount Helix is worst in September — around 26 µg/m³ PM2.5 (moderate), about 3.4× the cleanest month (May, 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) | 12 | 12 | 12 | 11 | 8 | 11 | 11 | 15 | 26 | 14 | 12 | 16 |
| Level | Good | Moderate | Moderate | Good | Good | Good | Good | Moderate | Moderate | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 12 | Good |
| Feb | 12 | Moderate |
| Mar | 12 | Moderate |
| Apr | 11 | Good |
| May | 8 | Good |
| Jun | 11 | Good |
| Jul | 11 | Good |
| Aug | 15 | Moderate |
| Sep | 26 | Moderate |
| Oct | 14 | Moderate |
| Nov | 12 | Moderate |
| Dec | 16 | Moderate |
Where is Casa de Oro-Mount Helix?
Casa de Oro-Mount Helix sits at 32.8°N, 117.0°W, 840 ft above sea level, in United States. The nearest listed city is El Cajon, 1.9 mi away.
Topography around Casa de Oro-Mount Helix
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Casa de Oro-Mount Helix.
Within 2 miles, the terrain around Casa de Oro-Mount Helix has significant variations in elevation — a maximum elevation change of 932 ft around an average of 643 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,762 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 6,430 ft.
The land around Casa de Oro-Mount Helix is covered by artificial surfaces (59%) and trees (31%) within 2 miles, artificial surfaces (40%) and shrubs (26%) within 10 miles, and shrubs (27%) and water (27%) 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 Casa de Oro-Mount Helix (32.764°, -116.9688°, elevation 840 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.