Hetch Hetchy, CA Climate: Temperature & Rain by Month
Annual temperature and rainfall from NOAA NCEI's 1991–2020 normals →; comfort score computed by PlainClimate
30-year climate normals (1991-2020) from Hetch Hetchy's primary NOAA station, HETCH HETCHY.
The climate verdict for Hetch Hetchy
Hetch Hetchy, California has a mixed annual climate rather than one dominant extreme. Its NOAA normal shows an annual average of 55°F. Its climate comfort score of 58/100 (moderate) lands mid-pack nationally, exceeding 37% of station-mapped location scores.
- 55°F
- annual average temperature (NOAA normal)
- 58/100
- comfort score, above 37% of station-mapped location scores
- 36.9"
- annual precipitation · 51" snow
- 210 days
- growing season, frost-free days
Hetch Hetchy: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00043939 · Hetch Hetchy, CA 55°F mean · 36.9" precip
TEMP-COOL · RANK-UPPER · PHOTO-FINISH · PRCP-MID · SWING-MID · COMF-MID · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COOL 55°F
- RANK-UPPER #4,117
- PHOTO-FINISH ≈ Pleasant Valley
- PRCP-MID 36.9"
- SWING-MID 33°F
- COMF-MID 58/100
- LOAD-HEAT 4,377 HDD
- STN-1 USC00043939
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Pleasant Valley, AZ (+ 0 °F mean)
Instrument codes from this station's NOAA 1991–2020 normals, mean temperature, corpus warmth rank, photo-finish peer station, precipitation band, seasonal swing, comfort composite, degree-day load, and field book, not a livability rating.
Mean-temperature neighbourhood
Nationwide NOAA normal poles and nearest peers, not a reprint of every CA station list.
- Hetch Hetchy (this station) 55°F
- Hot Candler, NC 55°F
- Near Pleasant Valley, AZ 55°F
- Near Weaverville, CA 55°F
- Near Robbinsville Ag, NC 55°F
Climate Living Index · Hetch Hetchy
Hetch Hetchy: 74/100 · grade B
Hetch Hetchy publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 1 missing weight rescale to 100.
PlainClimate-derived for Hetch Hetchy, not an official NOAA rating. Rankings still use Comfort Score 58/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Normal heat + freeze calendar | 8 calendar days | 100/100 · A |
| Precipitation balance | 36.9 in · 1.9 from 35 in | 92/100 · A |
| Frost-free season | 210 days/year | 71/100 · B |
| Annual temperature balance | 54.9°F · 12.6° from 67.5°F | 59/100 · C |
| Snowfall burden | 51.4 inches/year | 20/100 · F |
Hetch Hetchy · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Hetch Hetchy is a temperate Köppen climate: Csa
Coldest-month mean 39.8°F and warmest-month mean 72.5°F place this station in temperate, dry-summer, hot summer climates (Csa). Class Csa is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: temperate, specifically temperate, dry-summer, hot summer.
- Köppen code
- Csa
- Group
- Temperate
- Warmest month
- 72.5°F
- Coldest month
- 39.8°F
Source: official public datasets monthly normals (1991–2020) at the city’s primary station. This is a station classification, not a mapped regional consensus.
National standing · heating-led station
Where Hetch Hetchy sits across the climate record
Three NOAA fields for Hetch Hetchy's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- 60th percentile warmth
- Mid-pack annual mean versus 6,861 station normals.
- Annual precipitation
- 51st percentile wetness
- Neither arid nor torrential versus 6,352 station totals.
- Seasonal temperature swing
- Narrower than 87%
- Warmest-to-coldest month gap for Hetch Hetchy is compact versus 6,861 complete station-years.
How Hetch Hetchy compares across U.S. station-mapped locations
Hetch Hetchy's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
58 37th percentile score exceeds 37% of 6,189 station-mapped location scores
- 0–10: 0 station-mapped locations (0%). Below this entry.
- 10–20: 0 station-mapped locations (0%). Below this entry.
- 20–30: 96 station-mapped locations (2%). Below this entry.
- 30–40: 280 station-mapped locations (5%). Below this entry.
- 40–50: 1,113 station-mapped locations (18%). Below this entry.
- 50–60: 1,329 station-mapped locations (21%). This entry sits in this band.
- 60–70: 1,236 station-mapped locations (20%). Above this entry.
- 70–80: 650 station-mapped locations (11%). Above this entry.
- 80–90: 921 station-mapped locations (15%). Above this entry.
- 90–100: 564 station-mapped locations (9%). Above this entry.
Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020
Hetch Hetchy's measured station temperature trend
MethodologyAcross 78 complete annual observations from 1911 to 2024, HETCH HETCHY warmed at a fitted rate of 0.09°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Hetch Hetchy primary station fitted change +0.09 °C/decade
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 48°F (9°C) | 32°F (0°C) | 40°F (5°C) | 6.3" | 9.7" | 16.7 | 0.0 |
| February | 52°F (11°C) | 33°F (1°C) | 43°F (6°C) | 5.7" | 13.5" | 13.4 | 0.0 |
| March | 57°F (14°C) | 36°F (2°C) | 46°F (8°C) | 5.7" | 10.8" | 10.1 | 0.0 |
| April | 62°F (17°C) | 39°F (4°C) | 51°F (10°C) | 3.5" | 4.3" | 5.2 | 0.0 |
| May | 69°F (21°C) | 46°F (8°C) | 58°F (14°C) | 2.4" | 0.1" | 0.5 | 0.1 |
| June | 78°F (26°C) | 53°F (12°C) | 66°F (19°C) | 0.6" | 0.0" | 0.0 | 1.8 |
| July | 86°F (30°C) | 59°F (15°C) | 73°F (23°C) | 0.3" | 0.0" | 0.0 | 9.0 |
| August | 86°F (30°C) | 59°F (15°C) | 72°F (22°C) | 0.1" | 0.0" | 0.0 | 8.3 |
| September | 81°F (27°C) | 54°F (12°C) | 67°F (20°C) | 0.4" | 0.0" | 0.0 | 2.9 |
| October | 70°F (21°C) | 45°F (7°C) | 58°F (14°C) | 2.1" | 0.0" | 0.7 | 0.2 |
| November | 57°F (14°C) | 37°F (3°C) | 47°F (8°C) | 3.8" | 3.0" | 7.3 | 0.0 |
| December | 47°F (8°C) | 33°F (0°C) | 40°F (4°C) | 5.9" | 10.0" | 16.5 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 87°F around July 23, short of 90°F on every date, while 8 dates carry a normal low at or below freezing, the coldest 32°F near January 1.
The freezing stretch
The normal low stays at or below 32°F into January 6, then returns to freezing around December 30, covering 8 dates in all.
Derived from the normal daily minimum. This is a different measure from the 50%-probability frost dates shown elsewhere on this page, which come from NOAA’s frost product.
Where the wet dates fall
The likeliest wet date is February 27, when 38% of years recorded at least a hundredth of an inch. The driest is August 5 at 3%. Summed across the calendar, that is about 74 wet dates a year.
The widest day
August 31 carries the biggest normal gap between afternoon and dawn, 28°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Hetch Hetchy.
Monthly Precipitation
Average monthly rainfall and snowfall
Snow: 9.7"
10.5 days with precipitation
Snow: 13.5"
10.3 days with precipitation
Snow: 10.8"
11.0 days with precipitation
Snow: 4.3"
8.1 days with precipitation
Snow: 0.1"
6.4 days with precipitation
2.2 days with precipitation
1.1 days with precipitation
0.9 days with precipitation
2.0 days with precipitation
4.4 days with precipitation
Snow: 3.0"
7.0 days with precipitation
Snow: 10.0"
9.9 days with precipitation
Hetch Hetchy's wet season runs through the cold months
December, January and February carry 49% of the year's precipitation here, while June through August contribute 3%. That is the cool-season-dominant pattern of the West Coast and the higher inland West, where storm tracks swing south in winter and summer turns dry; the thermometer meanwhile shows a 32.7°F seasonal spread.
- Wettest month
- January, 6.3"
- Driest month
- August, 0.1"
- Wettest three months
- January, December, March (49% of the year)
Shares are computed from this station's own 1991-2020 monthly precipitation normals. A cool-season label means the December-February share reaches 35%. Where snow falls, the monthly figures above report liquid-equivalent precipitation, so a wet winter month is not necessarily a rainy one.
When it rains in Hetch Hetchy, it arrives in quantity
36.9" of precipitation falls across only about 74 wet days here, averaging 0.50 inches each. Fewer days carry more water: the year's total is delivered in comparatively heavy events rather than persistent damp.
- Days with measurable precipitation
- about 74 a year, 20% of all days
- Average depth per wet day
- 0.50 inches
- Most wet days
- March, about 11
- Fewest wet days
- August, about 1
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year, and a per-day average is not a forecast of any individual storm.
Winter brings real snow to Hetch Hetchy
Hetch Hetchy averages 51.4 inches of snowfall a year, with February the snowiest month on the normals, spread across roughly 14 days that record measurable snow. That is depth accumulating on the ground, which is why it can exceed the annual precipitation figure: precipitation counts the liquid the snow melts down to, and fresh snow is mostly air.
- Annual snowfall: 51.4 inches of depth.
- Days recording measurable snow: about 14 a year.
- At a rough ten-to-one melt ratio, snow accounts for on the order of 14% of the year's precipitation.
NOAA 1991-2020 normals. The ten-to-one ratio is a convention, not a measurement: real ratios vary with temperature, so treat the share as an order of magnitude rather than an exact split.
Frost Dates & Growing Season
First Fall Freeze
November 12
50% probability date
Last Spring Freeze
April 16
50% probability date
Growing Season
210 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
4,377
Higher = more heating needed
Cooling Degree Days
729
Higher = more cooling needed
Warmest Month
July
Coldest Month
December
Nationwide similar cities
Other rankable U.S. places outside CA closest to Hetch Hetchy on two NOAA annual-normal axes (mean temperature and annual precipitation). Chip rows use distinct link sets.
Closest by average temperature
Nearest out-of-state peers by annual mean temperature (55°F here).
- Booneville, KY 55°F · 0.0°F off
- California, MO 55°F · 0.0°F off
- Cave Junction, OR 55°F · 0.0°F off
- Clendenin, WV 55°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (36.9" here), excluding temperature-peer places.
- Rushford, MN 36.9" · 0.0" off
- Portland, OR 36.9" · 0.0" off
- Troy, KS 36.8" · 0.0" off
- Walnut, IL 36.8" · 0.0" off
Snow and freeze rhythm
When cold and snow define Hetch Hetchy
heating led · moderate · mid swing
Hetch Hetchy's energy balance leans toward cold weather: 4,377 annual heating degree days against 729 for cooling. Its 32.7°F seasonal range still makes the monthly rows more useful than the annual average alone.
Hetch Hetchy's frost-free season lasts about 210 days, a middle-length window whose endpoints matter more than the annual average. It describes freeze probability, not year-specific planting conditions.
-
1. Hetch Hetchy coldest normal
December
The coldest month still averages 40°F (4°C), above freezing, so this calendar has no hard winter.
-
2. Hetch Hetchy typical freeze period
January through December
The station reports average freezing days from January through December.
-
3. Hetch Hetchy snow peak
February
Hetch Hetchy averages 51.4 inches of snow a year, with February the snowiest month on the normals.
Questions about Hetch Hetchy's climate
How much snow does Hetch Hetchy get? ▼
How much energy does heating and cooling require in Hetch Hetchy? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Hetch Hetchy's primary station: HETCH HETCHY (USC00043939). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The conservative exact name-and-state crosswalk finds no Census place match, so PlainClimate treats this as a station-mapped location and does not claim it is a municipality. No exact Gazetteer row for Hetch Hetchy; facility counts that depend on place identity are therefore an upper bound, not a municipal census.
On this page every temperature, precipitation, and derived score for Hetch Hetchy comes from its primary NOAA station record. No figure on this page is typed in by an editor - each value is rendered from NOAA 1991-2020 U.S. Climate Normals. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 1991–2020 normals.