Discovery Bay, CA climate
Discovery Bay has mild winters and warm summers, with very little rain. A typical July afternoon reaches 92°, a January night drops to 40°, and snow is almost unheard of.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Discovery Bay feels like
Winter
Spring
Summer
Fall
Discovery Bay 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 | 57° | 40° | 2.7" | 0 | 13 | 0 | 44° – 54° |
| February | 62° | 43° | 2.4" | 0 | 10 | 0 | 48° – 57° |
| March | 68° | 45° | 1.8" | 0 | 8 | 0 | 50° – 63° |
| April | 73° | 48° | 0.9" | 0 | 5 | 0 | 55° – 65° |
| May | 80° | 53° | 0.5" | 0 | 3 | 0 | 59° – 74° |
| June | 87° | 58° | 0.1" | 0 | 1 | 0 | 68° – 75° |
| July | 92° | 60° | 0.0" | 0 | 0 | 0 | 72° – 80° |
| August | 91° | 59° | 0.0" | 0 | 0 | 0 | 72° – 80° |
| September | 88° | 57° | 0.1" | 0 | 1 | 0 | 69° – 76° |
| October | 79° | 52° | 0.6" | 0 | 3 | 0 | 62° – 72° |
| November | 66° | 45° | 1.3" | 0 | 7 | 0 | 50° – 60° |
| December | 57° | 40° | 2.4" | 0 | 12 | 0 | 45° – 52° |
| Year | 75° | 50° | 12.8" | 0.0" | 61 | 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 Discovery Bay
Discovery Bay gets 13 inches of rain and melted snow a year. January is the wettest month and July the driest. Rain or snow falls on about 61 days a year.
About 330 frost-free days a year
In half of years the last 32° night comes by January 19 and the first one by December 10. That leaves about 330 frost-free days for gardens, longer than 96% of U.S. towns.
Heating and cooling a home in Discovery Bay
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Discovery Bay, 57% of that work is heating and 43% 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 Discovery Bay 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 Discovery Bay averaged 1.5° warmer than the 1900s. The biggest change is in January (+2.2°). The shift is larger than in 71% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Discovery Bay’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 59° to 74°. June is the most reliable, staying within 8°.
Common questions about Discovery Bay’s climate
What is the coldest month in Discovery Bay?
December, with a typical high of 57° and a low of 40°.
What is the hottest month in Discovery Bay?
July, with a typical high of 92° and a low of 60°. About 82 days a year reach 90°.
How much snow does Discovery Bay get?
Almost none. A normal year brings 0.0 inches.
When is the first frost in Discovery Bay?
In half of years the first 32° night comes by December 10, and the last spring frost by January 19.
What is the rainiest month in Discovery Bay?
January, with 2.7 inches of rain and melted snow. The year totals 13 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Discovery Bay itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Tracy Pumping Plt, CA (8 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.