Fullerton weather in January: Fullerton, California: normal highs, lows, rain and records for January
Fullerton in January has a normal high of 69°F and a normal low of 46°F, a daily mean of 58°F, holding near 69°F all month. Measurable precipitation falls on 5 days in a normal January, 2.85 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 20°C and low of 8°C, 72 mm of precipitation in January.
- NOAA stationFullerton Municipal Airport
- Station IDUSW00003166
- Location33.87°N 117.98°W
- Elevation96 ft (29 m)
- From the center3 miles
- Population140,054
- Jan 69° 46°
- Feb 69° 48°
- Mar 71° 52°
- Apr 74° 54°
- May 76° 58°
- Jun 79° 63°
- Jul 84° 66°
- Aug 87° 66°
- Sep 85° 65°
- Oct 80° 58°
- Nov 74° 51°
- Dec 68° 46°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Fullerton in January?
The normal high is 69°F and the normal low 46°F, for a daily mean of 57.6°F. January is 0.7°F warmer than December and 1.0°F cooler than February. January is the 11th warmest month of the year in Fullerton and the 2nd wettest. Across the month the normal high rises 1°F, from 68°F on January 1 to 69°F on January 31. From one year to the next January's mean temperature typically moves about 2.2°F either way (NOAA's standard deviation), so roughly two Januarys in three average between 55°F and 60°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 19%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| January 1 | 68°F | 46°F | 19% | 11% |
| January 8 | 69°F | 46°F | 18% | 11% |
| January 15 | 69°F | 46°F | 17% | 11% |
| January 22 | 69°F | 47°F | 17% | 11% |
| January 31 | 69°F | 47°F | 19% | 12% |
Every day of January: normal high, low and chance of precipitation (warmest afternoon January 15, coldest night January 1)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| January 1 | 68°F | 46°F | 19% | 11% | 10 h |
| January 2 | 68°F | 46°F | 19% | 11% | 10 h |
| January 3 | 68°F | 46°F | 19% | 11% | 10 h |
| January 4 | 69°F | 46°F | 19% | 11% | 10 h |
| January 5 | 69°F | 46°F | 18% | 11% | 10 h |
| January 6 | 69°F | 46°F | 18% | 11% | 10 h |
| January 7 | 69°F | 46°F | 18% | 11% | 10 h |
| January 8 | 69°F | 46°F | 18% | 11% | 10 h |
| January 9 | 69°F | 46°F | 18% | 11% | 10 h |
| January 10 | 69°F | 46°F | 18% | 11% | 10 h |
| January 11 | 69°F | 46°F | 17% | 11% | 10 h |
| January 12 | 69°F | 46°F | 17% | 11% | 10 h |
| January 13 | 69°F | 46°F | 17% | 11% | 10 h 10 min |
| January 14 | 69°F | 46°F | 17% | 11% | 10 h 10 min |
| January 15 | 69°F | 46°F | 17% | 11% | 10 h 10 min |
| January 16 | 69°F | 47°F | 17% | 11% | 10 h 10 min |
| January 17 | 69°F | 47°F | 17% | 11% | 10 h 10 min |
| January 18 | 69°F | 47°F | 17% | 11% | 10 h 10 min |
| January 19 | 69°F | 47°F | 17% | 11% | 10 h 10 min |
| January 20 | 69°F | 47°F | 17% | 11% | 10 h 10 min |
| January 21 | 69°F | 47°F | 17% | 11% | 10 h 20 min |
| January 22 | 69°F | 47°F | 17% | 11% | 10 h 20 min |
| January 23 | 69°F | 47°F | 17% | 11% | 10 h 20 min |
| January 24 | 69°F | 47°F | 18% | 11% | 10 h 20 min |
| January 25 | 69°F | 47°F | 18% | 11% | 10 h 20 min |
| January 26 | 69°F | 47°F | 18% | 12% | 10 h 20 min |
| January 27 | 69°F | 47°F | 18% | 12% | 10 h 20 min |
| January 28 | 69°F | 47°F | 18% | 12% | 10 h 30 min |
| January 29 | 69°F | 47°F | 18% | 12% | 10 h 30 min |
| January 30 | 69°F | 47°F | 19% | 12% | 10 h 30 min |
| January 31 | 69°F | 47°F | 19% | 12% | 10 h 30 min |
- Normal high
- 69°FJanuary average
- Normal low
- 46°FJanuary average
- Precipitation
- 2.85 inmonth total
- Days with precipitation
- 50.01 inch or more
- Daylight
- 10 h to 10 h 30 minJanuary 1 to January 31
- Days at 70°F or more
- 15
- Days at 80°F or more
- 4
- Sunshine
- 85%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00003166; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Fullerton in January?
On a given January day the chance of 0.01 inch or more is 18% on average, highest around January 1 (19%). In all, 2.85 in falls on 5 days of a normal January, 1 of them with an inch or more.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00003166.
What are the records for January in Fullerton?
The warmest January temperature on this station's record (since 1998) is 94°F, on January 31, 2003; the coldest is 28°F, on January 14, 2007. The wettest January brought 7.13 in (2017).
The January mean against the 1991-2020 normal of 57.6°F: 2021 58.6°F (+1.0), 2022 58.8°F (+1.2), 2023 56.0°F (−1.6), 2024 57.2°F (−0.4), 2025 56.6°F (−1.0), 2026 60.6°F (+3.0). 3 of 6 ran warmer than normal.
| January | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 58.6°F | +1.0°F | 1.55 in |
| 2022 | 58.8°F | +1.2°F | 0.04 in |
| 2023 | 56.0°F | −1.6°F | 5.52 in |
| 2024 | 57.2°F | −0.4°F | 1.55 in |
| 2025 | 56.6°F | −1.0°F | 0.37 in |
| 2026 | 60.6°F | +3.0°F | 1.93 in |
Source: records: ACIS, station USW00003166; recent months: ACIS, station USW00003166. Records and recent months use complete months only.
How does January in Fullerton compare across California?
Across the 219 places PlainClimate covers in California, January normal highs run from 37°F in Tahoma to 72°F in Brawley; Fullerton's is 69°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.