Jamestown, CA climate
Jamestown has mild winters and hot summers. A typical July afternoon reaches 94°, a January night drops to 35°, and snow is almost unheard of.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Jamestown feels like
Winter
Spring
Summer
Fall
Jamestown weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 56° | 35° | 5.7" | 0 | 10 | 0 | 42° – 50° |
| February | 59° | 37° | 5.0" | 0 | 10 | 0 | 44° – 54° |
| March | 63° | 39° | 5.0" | 0 | 10 | 0 | 44° – 57° |
| April | 68° | 42° | 2.7" | 0 | 6 | 0 | 50° – 59° |
| May | 78° | 48° | 1.3" | 0 | 4 | 0 | 55° – 70° |
| June | 87° | 53° | 0.3" | 0 | 1 | 0 | 65° – 75° |
| July | 94° | 59° | 0.0" | 0 | 0 | 0 | 72° – 80° |
| August | 93° | 58° | 0.0" | 0 | 1 | 0 | 72° – 79° |
| September | 88° | 54° | 0.2" | 0 | 1 | 0 | 66° – 75° |
| October | 77° | 46° | 1.5" | 0 | 4 | 0 | 58° – 68° |
| November | 64° | 39° | 3.1" | 0 | 7 | 0 | 43° – 57° |
| December | 55° | 34° | 5.2" | 0 | 10 | 0 | 41° – 50° |
| Year | 74° | 45° | 30.0" | 0.0" | 64 | 0 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Jamestown
Jamestown gets 30 inches of rain and melted snow a year. January is the wettest month and July the driest. Rain or snow falls on about 64 days a year.
About 213 frost-free days a year
In half of years the last 32° night comes by April 9 and the first one by November 9. That leaves about 213 frost-free days for gardens, longer than 79% of U.S. towns.
Heating and cooling a home in Jamestown
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Jamestown, 79% of that work is heating and 21% is cooling.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
How Jamestown compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Jamestown averaged 1.0° warmer than the 1900s. The biggest change is in January (+2.2°). The shift is smaller than in 72% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Jamestown’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. May swings the most: between 1991 and 2020 its average temperature ranged from 55° to 70°. August is the most reliable, staying within 8°.
Common questions about Jamestown’s climate
What is the coldest month in Jamestown?
December, with a typical high of 55° and a low of 34°.
What is the hottest month in Jamestown?
July, with a typical high of 94° and a low of 59°. About 75 days a year reach 90°.
How much snow does Jamestown get?
Almost none. A normal year brings 0.0 inches.
When is the first frost in Jamestown?
In half of years the first 32° night comes by November 9, and the last spring frost by April 9.
What is the rainiest month in Jamestown?
January, with 5.7 inches of rain and melted snow. The year totals 30 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Jamestown itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Sonora, CA (1 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.