Clearlake in Fall
In fall (September, October and November), Clearlake sees average daytime highs around 71°F and overnight lows near 51°F, with 4.9 in of rain over about 12 wet days across the season. It is the 2nd-warmest season and the 3rd-wettest season.
Over the season highs ease from about 85°F in early September to 55°F by late November. The sky is clear or mostly clear about 65% of the time across fall, and the air most often feels dry.
Fall is Clearlake's best season of the year to visit on our travel score. For the whole year in context, see Clearlake's year-round climate.
- Avg daytime high
- 71°F
- 2nd-warmest season
- Avg overnight low
- 51°F
- Rainfall
- 4.9 in
- 12 wet days
- Avg wind
- 4 mph
- Travel score
- 7.2
- best season of the year
- Months
- Sep · Oct · Nov
Temperature in Clearlake in Fall
Over the season highs ease from about 85°F in early September to 55°F by late November.
A typical fall day in Clearlake reaches about 71°F and drops to 51°F overnight. The warmest of the three months is September, the coolest November.
Clearlake 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 | 53° / 38° | 6.1 | 10.9 | 1.4 | 9.6 | 2.8 |
| Feb | 55° / 40° | 5.9 | 9.4 | 1.7 | 10.5 | 3.6 |
| Mar | 59° / 42° | 4.7 | 10.4 | 1.4 | 11.7 | 4.6 |
| Apr | 64° / 45° | 2.1 | 6.5 | 0.3 | 13 | 6.2 |
| May | 71° / 51° | 1.4 | 4.7 | 0 | 14.1 | 7.8 |
| Jun | 80° / 58° | 0.5 | 2.1 | 0 | 14.7 | 8.2 |
| Jul | 87° / 64° | 0.0 | 0.2 | 0 | 14.5 | 6.6 |
| Aug | 86° / 63° | 0.1 | 0.4 | 0 | 13.5 | 6.7 |
| Sep | 82° / 59° | 0.2 | 1 | 0 | 12.3 | 8.2 |
| Oct | 72° / 52° | 1.6 | 3.8 | 0 | 11 | 8.2 |
| Nov | 60° / 43° | 3.2 | 7.1 | 0.2 | 9.9 | 5.1 |
| Dec | 52° / 38° | 6.2 | 10.5 | 0.8 | 9.3 | 2.8 |
Cloud cover in Fall
The sky is clear or mostly clear about 65% of the time across fall.
Chance of precipitation in Fall
Clearlake gets around 4.9 in of rain over 12 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 Clearlake
In fall, Clearlake overlaps its rainy season season. The full year is below, with each hazard's peak months called out.
Clearlake's rainy season runs November–March, when most of the year's rain falls.
Is fall a good time to visit Clearlake?
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 Clearlake for general sightseeing.
What to pack for Clearlake in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, Clearlake sees daytime highs around 71°F and nights near 51°F. Pack light clothes and sun protection. Worth having: a warm layer. About 12 days see rain.
UV index in Clearlake 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 Clearlake peaks around June 23 at about 10 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 15 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 | 5 | 6 | 9 | 10 | 10 | 9 | 6 | 5 | 2 | 2 |
| Level | Moderate | Moderate | Moderate | High | Very high | Extreme | Extreme | Very high | High | High | Moderate | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 2 | Moderate |
| Feb | 3 | Moderate |
| Mar | 5 | Moderate |
| Apr | 6 | High |
| May | 9 | Very high |
| Jun | 10 | Extreme |
| Jul | 10 | Extreme |
| Aug | 9 | Very high |
| Sep | 6 | High |
| Oct | 5 | High |
| Nov | 2 | Moderate |
| Dec | 2 | Low |
Air quality in Clearlake 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 Clearlake is worst in September — around 31 µg/m³ PM2.5 (moderate), about 5.8× the cleanest month (June, 5 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 | 8 | 9 | 8 | 6 | 5 | 14 | 29 | 31 | 14 | 8 | 6 |
| Level | Good | Good | Good | Good | Good | Good | Moderate | Moderate | Moderate | Moderate | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 6 | Good |
| Feb | 8 | Good |
| Mar | 9 | Good |
| Apr | 8 | Good |
| May | 6 | Good |
| Jun | 5 | Good |
| Jul | 14 | Moderate |
| Aug | 29 | Moderate |
| Sep | 31 | Moderate |
| Oct | 14 | Moderate |
| Nov | 8 | Good |
| Dec | 6 | Good |
Where is Clearlake?
Clearlake sits at 39.0°N, 122.6°W, 1,417 ft above sea level, in United States. The nearest listed city is Windsor, 30 mi away.
Topography around Clearlake
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Clearlake.
Within 2 miles, the terrain around Clearlake has significant variations in elevation — a maximum elevation change of 853 ft around an average of 1,493 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 3,409 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 6,982 ft.
The land around Clearlake is covered by trees (39%) and grassland (28%) within 2 miles, trees (52%) and grassland (38%) within 10 miles, and trees (52%) and grassland (30%) 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 Clearlake (38.9582°, -122.6264°, elevation 1,417 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.