Happy Valley in Fall
In fall (September, October and November), Happy Valley sees average daytime highs around 63°F and overnight lows near 46°F, with 17.1 in of precipitation over about 37 wet days across the season. It is the 2nd-warmest season and the 2nd-wettest season.
Over the season highs ease from about 78°F in early September to 47°F by late November. The sky is clear or mostly clear about 31% of the time across fall, and the air most often feels dry.
Fall is Happy Valley's 2nd-best season to visit on our travel score. For the whole year in context, see Happy Valley's year-round climate.
- Avg daytime high
- 63°F
- 2nd-warmest season
- Avg overnight low
- 46°F
- Precipitation
- 17.1 in
- 37 wet days
- Avg wind
- 5 mph
- Travel score
- 4.9
- 2nd-best season
- Months
- Sep · Oct · Nov
Temperature in Happy Valley in Fall
Over the season highs ease from about 78°F in early September to 47°F by late November.
A typical fall day in Happy Valley reaches about 63°F and drops to 46°F overnight. The warmest of the three months is September, the coolest November.
How fall really feels in Happy Valley
Once humidity and wind are folded in, fall brings about 0 days that feel above 90°F and 1 that feel at or below 32°F.
The story in fall is cold — wind chill drags the overnight "feels like" below the raw low.
Happy Valley 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 | 46° / 36° | 8.7 | 18.3 | 3.7 | 8.9 | 1.0 |
| Feb | 50° / 37° | 6.5 | 15.6 | 3.2 | 10.1 | 1.8 |
| Mar | 55° / 39° | 7.0 | 18.2 | 2.2 | 11.6 | 2.7 |
| Apr | 60° / 42° | 5.6 | 16.6 | 0.2 | 13.2 | 3.9 |
| May | 67° / 47° | 3.5 | 11.6 | 0 | 14.7 | 5.8 |
| Jun | 72° / 52° | 2.3 | 9 | 0 | 15.4 | 6.8 |
| Jul | 80° / 56° | 0.6 | 2.9 | 0 | 15.1 | 7.9 |
| Aug | 81° / 56° | 0.8 | 2.9 | 0 | 13.9 | 7.9 |
| Sep | 74° / 52° | 2.3 | 6.4 | 0 | 12.3 | 7.6 |
| Oct | 62° / 45° | 5.8 | 12.9 | 0 | 10.7 | 5.0 |
| Nov | 51° / 40° | 9.0 | 18 | 1.1 | 9.3 | 2.1 |
| Dec | 45° / 36° | 9.6 | 18.4 | 3.6 | 8.6 | 0.8 |
Cloud cover in Fall
The sky is clear or mostly clear about 31% of the time across fall.
Chance of precipitation in Fall
Happy Valley gets around 17.1 in of rain and snow over 37 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 5 mph across fall.
Sunrise & sunset in Fall
Daylight runs from about 13 h 06 min in early September to 8 h 48 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 2.8 kWh/m².
Hazard calendar for Happy Valley
In fall, Happy Valley overlaps its rainy season season. The full year is below, with each hazard's peak months called out.
Happy Valley's rainy season runs October–April, when most of the year's rain falls.
Is fall a good time to visit Happy Valley?
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 Happy Valley for sightseeing.
What to pack for Happy Valley in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, Happy Valley sees daytime highs around 63°F and nights near 46°F. Pack a warm layer and rain gear. Worth having: light clothes and sun protection. About 37 days see rain.
UV index in Happy Valley in Fall
Clear-sky midday UV across fall averages around 3. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Happy Valley peaks around July 17 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 15 at about 1 (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) | 1 | 2 | 4 | 5 | 8 | 7 | 8 | 7 | 4 | 3 | 1 | 1 |
| Level | Low | Low | Moderate | Moderate | Very high | High | Very high | High | Moderate | Moderate | Low | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 1 | Low |
| Feb | 2 | Low |
| Mar | 4 | Moderate |
| Apr | 5 | Moderate |
| May | 8 | Very high |
| Jun | 7 | High |
| Jul | 8 | Very high |
| Aug | 7 | High |
| Sep | 4 | Moderate |
| Oct | 3 | Moderate |
| Nov | 1 | Low |
| Dec | 1 | Low |
Air quality in Happy Valley 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 Happy Valley is worst in August — around 35 µg/m³ PM2.5 (moderate), about 6.3× the cleanest month (December, 6 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) | 6 | 7 | 10 | 10 | 9 | 8 | 8 | 35 | 33 | 11 | 8 | 6 |
| Level | Good | Good | Good | Good | Good | Good | Good | Moderate | Moderate | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 6 | Good |
| Feb | 7 | Good |
| Mar | 10 | Good |
| Apr | 10 | Good |
| May | 9 | Good |
| Jun | 8 | Good |
| Jul | 8 | Good |
| Aug | 35 | Moderate |
| Sep | 33 | Moderate |
| Oct | 11 | Good |
| Nov | 8 | Good |
| Dec | 6 | Good |
Where is Happy Valley?
Happy Valley sits at 45.4°N, 122.5°W, 502 ft above sea level, in United States. The nearest listed city is Lents, 3.1 mi away.
Topography around Happy Valley
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Happy Valley.
Within 2 miles, the terrain around Happy Valley has significant variations in elevation — a maximum elevation change of 883 ft around an average of 538 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,161 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 11,093 ft.
The land around Happy Valley is covered by trees (74%) within 2 miles, trees (59%) and artificial surfaces (20%) within 10 miles, and trees (78%) 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 Happy Valley (45.4468°, -122.5304°, elevation 502 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.