Tracy weather in December

In December, Tracy sees average daytime highs of 57°F and overnight lows near 41°F, with 3.0 in of rain across 8.3 wet days and about 9.4 hours of daylight. It is the 12th-warmest and 3rd-wettest month of the year here.

Highs ease over the month, from about 59°F in the first days to 55°F by the end. The sky is clear or mostly clear about 37% of the time in December, and the air most often feels dry.

Daylight stretches from about 9 h 36 min at the start of December to 9 h 24 min by month's end. Set against the rest of the year, December is Tracy's 10th-clearest and 9th-windiest month. For the whole year in context, see Tracy's year-round climate.

Daytime high: 57°; 12th warmest
Overnight low: 41°; 1st coldest
Rainfall: 3.0 in; 8.3 wet days
Daylight: 9 h 24 min; 7:20 AM – 4:44 PM
Cloud cover: 55%; 10th clearest
Wind: 4 mph; 9th windiest
Solar energy: 2.26 kWh/m²
Travel score: 4.2; out of 10

Tracy is city in San Joaquin County, California, United States.

Density: 1,509/km²; people per km²
Founded: 1910

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

← November Tracy year-round climate January →Best places to visit in December

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Temperature in December

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 59°F in the first days to 55°F by the end.

A typical December day in Tracy reaches about 57°F in the afternoon and slips back to 41°F overnight — a 16°F spread between the day's warmth and the night's chill. On most days the high lands between 51°F and 62°F. Set against its neighbours, December runs about 7°F cooler than November and on par with January.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Avg high (°F)	59	59	59	58	58	58	58	58	58	57	57	57	57	57	56	56	56	56	56	56	56	56	56	56	56	55	55	55	55	55	56
Avg low (°F)	42	42	42	42	42	42	42	42	42	42	42	41	41	41	41	41	41	41	40	40	40	40	40	40	40	40	40	40	40	40	40

	Avg high (°F)	Avg low (°F)
1	59	42
2	59	42
3	59	42
4	58	42
5	58	42
6	58	42
7	58	42
8	58	42
9	58	42
10	57	42
11	57	42
12	57	41
13	57	41
14	57	41
15	56	41
16	56	41
17	56	41
18	56	41
19	56	40
20	56	40
21	56	40
22	56	40
23	56	40
24	56	40
25	56	40
26	55	40
27	55	40
28	55	40
29	55	40
30	55	40
31	56	40

Tracy weather by month

How December compares with the rest of the year at a glance. December is the 12th-warmest and 3rd-wettest month here — the current month is highlighted below.

Month	High / Low (°F)	Rainfall (inches)	Wet days	Daylight (hours)	Travel score
Jan	57° / 41°	3.3	9.1	9.7	4.2
Feb	60° / 43°	3.2	8.7	10.5	5.0
Mar	65° / 46°	2.6	8.9	11.7	6.2
Apr	70° / 48°	1.3	5	12.9	7.5
May	77° / 53°	0.7	3.1	14	8.4
Jun	84° / 57°	0.1	0.8	14.6	7.5
Jul	88° / 60°	0.0	0.2	14.3	6.2
Aug	87° / 60°	0.1	0.2	13.5	6.5
Sep	83° / 57°	0.1	0.6	12.3	7.8
Oct	75° / 52°	0.8	2.7	11	8.6
Nov	64° / 46°	1.5	5.5	10	6.5
Dec	57° / 41°	3.0	8.3	9.4	4.2

Cloud cover in December

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 37% of the time in December.

Beyond those clear spells, partly cloudy skies cover about 13% of December, with mostly cloudy or overcast conditions the remaining 49%.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Clearer (%)	54	53	52	52	52	51	50	51	50	50	50	51	51	51	51	51	51	52	52	52	52	52	51	51	51	50	50	49	48	48	46
Cloudier (%)	46	47	48	48	48	49	50	49	50	50	50	49	49	49	49	49	49	48	48	48	48	48	49	49	49	50	50	51	52	52	54

	Clearer (%)	Cloudier (%)
1	54	46
2	53	47
3	52	48
4	52	48
5	52	48
6	51	49
7	50	50
8	51	49
9	50	50
10	50	50
11	50	50
12	51	49
13	51	49
14	51	49
15	51	49
16	51	49
17	51	49
18	52	48
19	52	48
20	52	48
21	52	48
22	52	48
23	51	49
24	51	49
25	51	49
26	50	50
27	50	50
28	49	51
29	48	52
30	48	52
31	46	54

Chance of precipitation in December

Any precipitation

Tracy gets around 3.0 in of rain over 8.3 wet days in December. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 27% and peaks near 28% on the wettest days.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Rain chance (%)	26	26	27	27	28	28	28	28	28	28	28	28	28	28	28	28	27	27	27	26	26	26	26	26	26	26	26	26	26	27	27

	Rain chance (%)
1	26
2	26
3	27
4	27
5	28
6	28
7	28
8	28
9	28
10	28
11	28
12	28
13	28
14	28
15	28
16	28
17	27
18	27
19	27
20	26
21	26
22	26
23	26
24	26
25	26
26	26
27	26
28	26
29	26
30	27
31	27

Humidity in December

DryComfortableHumidMuggyOppressiveMiserable

Most of December feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, December lands in the dry band about 99% of days. It rarely turns muggy — the humid and sticky bands barely register.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Dry (%)	99	99	98	98	98	98	98	98	98	98	98	99	99	99	99	99	99	99	99	99	99	99	99	99	99	99	99	99	99	99	99
Comfortable (%)	1	1	2	2	2	2	2	2	2	2	2	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1

	Dry (%)	Comfortable (%)
1	99	1
2	99	1
3	98	2
4	98	2
5	98	2
6	98	2
7	98	2
8	98	2
9	98	2
10	98	2
11	98	2
12	99	1
13	99	1
14	99	1
15	99	1
16	99	1
17	99	1
18	99	1
19	99	1
20	99	1
21	99	1
22	99	1
23	99	1
24	99	1
25	99	1
26	99	1
27	99	1
28	99	1
29	99	1
30	99	1
31	99	1

Wind in December

Winds average 4 mph in December.

Across December, daily wind ranges from about 4 mph on the calmest days to 4 mph at its breeziest. It stays fairly steady from day to day.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Wind speed (mph)	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4
Feels	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm

	Wind speed (mph)	Feels
1	4	calm
2	4	calm
3	4	calm
4	4	calm
5	4	calm
6	4	calm
7	4	calm
8	4	calm
9	4	calm
10	4	calm
11	4	calm
12	4	calm
13	4	calm
14	4	calm
15	4	calm
16	4	calm
17	4	calm
18	4	calm
19	4	calm
20	4	calm
21	4	calm
22	4	calm
23	4	calm
24	4	calm
25	4	calm
26	4	calm
27	4	calm
28	4	calm
29	4	calm
30	4	calm
31	4	calm

Sunrise & sunset in December

DaylightNight

Daylight runs from about 9 h 36 min at the start of December to 9 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 12 minutes over December. Sunrise moves from 7:08 AM to 7:26 AM, and sunset from 4:43 PM to 4:52 PM.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Daylight (h)	9.6	9.6	9.5	9.5	9.5	9.5	9.5	9.5	9.5	9.5	9.4	9.4	9.4	9.4	9.4	9.4	9.4	9.4	9.4	9.4	9.4	9.4	9.4	9.4	9.4	9.4	9.4	9.4	9.4	9.4	9.4
Sunrise (AM)	7:08	7:09	7:10	7:11	7:12	7:12	7:13	7:14	7:15	7:16	7:16	7:17	7:18	7:19	7:19	7:20	7:20	7:21	7:22	7:22	7:23	7:23	7:24	7:24	7:24	7:25	7:25	7:25	7:26	7:26	7:26
Sunset (PM)	4:43	4:43	4:43	4:43	4:42	4:42	4:42	4:42	4:43	4:43	4:43	4:43	4:43	4:43	4:44	4:44	4:44	4:45	4:45	4:45	4:46	4:46	4:47	4:47	4:48	4:48	4:49	4:50	4:50	4:51	4:52

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	9.6	7:08	4:43
2	9.6	7:09	4:43
3	9.5	7:10	4:43
4	9.5	7:11	4:43
5	9.5	7:12	4:42
6	9.5	7:12	4:42
7	9.5	7:13	4:42
8	9.5	7:14	4:42
9	9.5	7:15	4:43
10	9.5	7:16	4:43
11	9.4	7:16	4:43
12	9.4	7:17	4:43
13	9.4	7:18	4:43
14	9.4	7:19	4:43
15	9.4	7:19	4:44
16	9.4	7:20	4:44
17	9.4	7:20	4:44
18	9.4	7:21	4:45
19	9.4	7:22	4:45
20	9.4	7:22	4:45
21	9.4	7:23	4:46
22	9.4	7:23	4:46
23	9.4	7:24	4:47
24	9.4	7:24	4:47
25	9.4	7:24	4:48
26	9.4	7:25	4:48
27	9.4	7:25	4:49
28	9.4	7:25	4:50
29	9.4	7:26	4:50
30	9.4	7:26	4:51
31	9.4	7:26	4:52

Solar energy in December

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in December, about 2.26 kWh/m² — the year's lowest.

For context, solar energy here swings from a low near 2.26 kWh/m² to a high of 8.27 kWh/m² in July across the year — December's 2.26 kWh/m² sits near the bottom.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Solar energy (kWh/m²)	2.4	2.4	2.3	2.3	2.3	2.3	2.3	2.3	2.2	2.2	2.2	2.2	2.2	2.2	2.2	2.2	2.2	2.2	2.2	2.2	2.2	2.2	2.2	2.3	2.3	2.3	2.3	2.3	2.3	2.3	2.3
Level	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate

	Solar energy (kWh/m²)	Level
1	2.4	Moderate
2	2.4	Moderate
3	2.3	Moderate
4	2.3	Moderate
5	2.3	Moderate
6	2.3	Moderate
7	2.3	Moderate
8	2.3	Moderate
9	2.2	Moderate
10	2.2	Moderate
11	2.2	Moderate
12	2.2	Moderate
13	2.2	Moderate
14	2.2	Moderate
15	2.2	Moderate
16	2.2	Moderate
17	2.2	Moderate
18	2.2	Moderate
19	2.2	Moderate
20	2.2	Moderate
21	2.2	Moderate
22	2.2	Moderate
23	2.2	Moderate
24	2.3	Moderate
25	2.3	Moderate
26	2.3	Moderate
27	2.3	Moderate
28	2.3	Moderate
29	2.3	Moderate
30	2.3	Moderate
31	2.3	Moderate

Planning a trip in December

Is December a good time to visit Tracy?

Our two travel scores rate December for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

4.2

Sightseeing

11th-best month of the year

0.0

Beach & pool

11th-best month of the year

December is a reasonable time to visit Tracy for sightseeing.

What to pack for Tracy in December

From December's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In December, Tracy sees daytime highs around 57°F and nights near 41°F. Worth packing: a warm layer and rain gear. About 8 days see rain.

a warm layerrain gear

UV index in Tracy in December

LowModerateHighVery highExtreme

Clear-sky midday UV in December peaks around 2. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Tracy peaks around June 22 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	4	4	7	8	10	10	10	6	5	2	2
Level	Moderate	Moderate	Moderate	High	Very high	Extreme	Extreme	Very high	High	High	Moderate	Moderate

	UV index (midday)	Level
Jan	2	Moderate
Feb	4	Moderate
Mar	4	Moderate
Apr	7	High
May	8	Very high
Jun	10	Extreme
Jul	10	Extreme
Aug	10	Very high
Sep	6	High
Oct	5	High
Nov	2	Moderate
Dec	2	Moderate

Air quality in Tracy in December

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where December falls, not just the annual average.

Air quality in Tracy is worst in August — around 34 µg/m³ PM2.5 (moderate), about 4.9× the cleanest month (June, 7 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)	13	13	13	10	8	7	9	34	16	14	15	12
Level	Moderate	Moderate	Moderate	Good	Good	Good	Good	Moderate	Moderate	Moderate	Moderate	Good

	PM2.5 (µg/m³)	Level
Jan	13	Moderate
Feb	13	Moderate
Mar	13	Moderate
Apr	10	Good
May	8	Good
Jun	7	Good
Jul	9	Good
Aug	34	Moderate
Sep	16	Moderate
Oct	14	Moderate
Nov	15	Moderate
Dec	12	Good

Location & terrain

Where is Tracy?

Tracy sits at 37.7°N, 121.4°W, 52 ft above sea level, in United States. The nearest listed city is Lathrop, 9.9 mi away.

Topography around Tracy

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Tracy.

Within 2 miles, the terrain around Tracy has only modest variations in elevation — a maximum elevation change of 118 ft around an average of 52 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,795 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 4,373 ft.

The land around Tracy is covered by artificial surfaces (64%) within 2 miles, grassland (41%) and cropland (31%) within 10 miles, and grassland (40%) and trees (24%) within 50 miles.

2 miles

118 ft

artificial surfaces 64%

10 miles

1,795 ft

grassland 41%

50 miles

4,373 ft

grassland 40%

treesgrasslandcroplandartificial surfacesbare terrainwaterwetland

← November Tracy year-round climate January →Best places to visit in December

December weather nearby: Lathrop 9.9 mi · Manteca 12 mi · Ripon 17 mi · Stockton 17 mi · Livermore 19 mi · Brentwood 20 mi · Oakley 24 mi · Modesto 24 mi

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 Tracy (37.7399°, -121.4262°, elevation 52 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. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).

	Avg high (°F)	Avg low (°F)
1	59	42
2	59	42
3	59	42
4	58	42
5	58	42
6	58	42
7	58	42
8	58	42
9	58	42
10	57	42
11	57	42
12	57	41
13	57	41
14	57	41
15	56	41
16	56	41
17	56	41
18	56	41
19	56	40
20	56	40
21	56	40
22	56	40
23	56	40
24	56	40
25	56	40
26	55	40
27	55	40
28	55	40
29	55	40
30	55	40
31	56	40

	Clearer (%)	Cloudier (%)
1	54	46
2	53	47
3	52	48
4	52	48
5	52	48
6	51	49
7	50	50
8	51	49
9	50	50
10	50	50
11	50	50
12	51	49
13	51	49
14	51	49
15	51	49
16	51	49
17	51	49
18	52	48
19	52	48
20	52	48
21	52	48
22	52	48
23	51	49
24	51	49
25	51	49
26	50	50
27	50	50
28	49	51
29	48	52
30	48	52
31	46	54

	Rain chance (%)
1	26
2	26
3	27
4	27
5	28
6	28
7	28
8	28
9	28
10	28
11	28
12	28
13	28
14	28
15	28
16	28
17	27
18	27
19	27
20	26
21	26
22	26
23	26
24	26
25	26
26	26
27	26
28	26
29	26
30	27
31	27

	Dry (%)	Comfortable (%)
1	99	1
2	99	1
3	98	2
4	98	2
5	98	2
6	98	2
7	98	2
8	98	2
9	98	2
10	98	2
11	98	2
12	99	1
13	99	1
14	99	1
15	99	1
16	99	1
17	99	1
18	99	1
19	99	1
20	99	1
21	99	1
22	99	1
23	99	1
24	99	1
25	99	1
26	99	1
27	99	1
28	99	1
29	99	1
30	99	1
31	99	1

	Avg high (°F)	Avg low (°F)
1	59	42
2	59	42
3	59	42
4	58	42
5	58	42
6	58	42
7	58	42
8	58	42
9	58	42
10	57	42
11	57	42
12	57	41
13	57	41
14	57	41
15	56	41
16	56	41
17	56	41
18	56	41
19	56	40
20	56	40
21	56	40
22	56	40
23	56	40
24	56	40
25	56	40
26	55	40
27	55	40
28	55	40
29	55	40
30	55	40
31	56	40

	Clearer (%)	Cloudier (%)
1	54	46
2	53	47
3	52	48
4	52	48
5	52	48
6	51	49
7	50	50
8	51	49
9	50	50
10	50	50
11	50	50
12	51	49
13	51	49
14	51	49
15	51	49
16	51	49
17	51	49
18	52	48
19	52	48
20	52	48
21	52	48
22	52	48
23	51	49
24	51	49
25	51	49
26	50	50
27	50	50
28	49	51
29	48	52
30	48	52
31	46	54

	Rain chance (%)
1	26
2	26
3	27
4	27
5	28
6	28
7	28
8	28
9	28
10	28
11	28
12	28
13	28
14	28
15	28
16	28
17	27
18	27
19	27
20	26
21	26
22	26
23	26
24	26
25	26
26	26
27	26
28	26
29	26
30	27
31	27

	Dry (%)	Comfortable (%)
1	99	1
2	99	1
3	98	2
4	98	2
5	98	2
6	98	2
7	98	2
8	98	2
9	98	2
10	98	2
11	98	2
12	99	1
13	99	1
14	99	1
15	99	1
16	99	1
17	99	1
18	99	1
19	99	1
20	99	1
21	99	1
22	99	1
23	99	1
24	99	1
25	99	1
26	99	1
27	99	1
28	99	1
29	99	1
30	99	1
31	99	1

	Avg high (°F)	Avg low (°F)
1	59	42
2	59	42
3	59	42
4	58	42
5	58	42
6	58	42
7	58	42
8	58	42
9	58	42
10	57	42
11	57	42
12	57	41
13	57	41
14	57	41
15	56	41
16	56	41
17	56	41
18	56	41
19	56	40
20	56	40
21	56	40
22	56	40
23	56	40
24	56	40
25	56	40
26	55	40
27	55	40
28	55	40
29	55	40
30	55	40
31	56	40

	Clearer (%)	Cloudier (%)
1	54	46
2	53	47
3	52	48
4	52	48
5	52	48
6	51	49
7	50	50
8	51	49
9	50	50
10	50	50
11	50	50
12	51	49
13	51	49
14	51	49
15	51	49
16	51	49
17	51	49
18	52	48
19	52	48
20	52	48
21	52	48
22	52	48
23	51	49
24	51	49
25	51	49
26	50	50
27	50	50
28	49	51
29	48	52
30	48	52
31	46	54

	Rain chance (%)
1	26
2	26
3	27
4	27
5	28
6	28
7	28
8	28
9	28
10	28
11	28
12	28
13	28
14	28
15	28
16	28
17	27
18	27
19	27
20	26
21	26
22	26
23	26
24	26
25	26
26	26
27	26
28	26
29	26
30	27
31	27

	Dry (%)	Comfortable (%)
1	99	1
2	99	1
3	98	2
4	98	2
5	98	2
6	98	2
7	98	2
8	98	2
9	98	2
10	98	2
11	98	2
12	99	1
13	99	1
14	99	1
15	99	1
16	99	1
17	99	1
18	99	1
19	99	1
20	99	1
21	99	1
22	99	1
23	99	1
24	99	1
25	99	1
26	99	1
27	99	1
28	99	1
29	99	1
30	99	1
31	99	1