Hottest (avg)
#11 / 12
On the cooler side.
January in context
How it compares to the rest of the year in San Francisco.
Wettest (avg)
#2 / 12
Among the wetter months.
Daylight Hours
#11 / 12
Shorter days.
Windiest (avg)
#10 / 12
Usually calmer than most months.
Highest UV
#11 / 12
UV is gentler than usual.
Most Humid
#1 / 12
The muggiest month of the year.
Monthly climate breakdown
A detailed look at the typical climate conditions for January.
Thermal profile
Temperature
Typical daytime high
- Nighttime low
-
- Feels like (avg)
-
Light window
Sunshine
9.9 h
Average daylight
- UV index (max)
- 4
- Typical sun hours
- 07:21 - 17:15
Wet-day pattern
Rain & Snow
Typical rainfall
- Rainy days
- 12 days
- Cloud cover (avg)
- 62%
Air feel
Humidity & Wind
83%
Average humidity
- Wind (avg)
-
- Wind (max gusts)
-
Historical daily baseline
Daily climate explorer
Pick a day to inspect the usual conditions through January in San Francisco. Based on a 30-year historical climate baseline, not a forecast.
Primary control
Select a day
Scroll to compare daily conditions. The summary updates with your selection.
Secondary context
Monthly trend
Median daytime highs across the month, with a softer low line.
Median temperatureMedian lowTypical range
Day 15 selected for January. Temperature 13.4°C.
Historical disruption baseline
Typical disruptions in January
Based on 30 years of historical data, these are the disruption patterns most likely to affect plans in January.
Cold High impact
Cold feels-like nights Measures: Cold feels-like nights (min <=5C). Observed about 59% of days (18.2 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
18.2 days / month
- Share of days
- ~59% of days
- Upper edge
- Up to ~5°C (P95)
Why this matters
Cold feels-like nights are possible on ~18 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Rain High impact
Rain disruption Measures: Likely rain disruption days. Observed about 20% of days (6.2 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
6.2 days / month
- Share of days
- ~20% of days
- Upper edge
- Up to ~35mm (P95)
Why this matters
Rain disruption risk appears on ~6 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Washout risk Measures: Washout day risk. Observed about 20% of days (6.1 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
6.1 days / month
- Share of days
- ~20% of days
- Upper edge
- Up to ~36mm (P95)
Why this matters
Washout conditions are possible on ~6 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Heavy rain days Measures: Heavy rain days (>=10mm). Observed about 12% of days (3.7 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
3.7 days / month
- Share of days
- ~12% of days
- Upper edge
- Up to ~40mm (P95)
Why this matters
Heavy rain is possible on ~4 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Wind High impact
Strong gusts Measures: Strong gust days (>=60 km/h). Observed about 8% of days (2.5 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
2.5 days / month
- Share of days
- ~8% of days
- Upper edge
- Up to ~95km/h (P95)
Why this matters
Strong gusts are possible on ~3 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Wind High impact
Stormy conditions Measures: Storm-impact proxy days. Observed about 8% of days (2.5 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
2.5 days / month
- Share of days
- ~8% of days
- Upper edge
- Up to ~95km/h (P95)
Why this matters
Stormy conditions are possible on ~2 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Show all disruptions (18 more)
Rain High impact
Washout run Measures: Multi-day washout runs. Observed about 1.5 days/month in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
1.5 days / month
- Share of days
- —
- Upper edge
- Up to ~34mm (P95)
Why this matters
Multi-day washout runs are possible on ~2 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Rain High impact
Very heavy rain Measures: Very heavy rain days (>=25mm). Observed about 3% of days (0.8 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.8 days / month
- Share of days
- ~3% of days
- Upper edge
- Up to ~47mm (P95)
Why this matters
Very heavy rain is possible on ~1 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Wind High impact
Severe gusts Measures: Severe gust days (>=80 km/h). Observed about 2% of days (0.5 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.5 days / month
- Share of days
- ~2% of days
- Upper edge
- Up to ~103km/h (P95)
Why this matters
Severe gusts are possible on ~1 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Visibility Moderate
Fog-likely signal Measures: Fog-likely visibility proxy. Observed about 8% of days (2.5 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
2.5 days / month
- Share of days
- ~8% of days
- Upper edge
- Up to ~97% (P95)
Why this matters
Fog-likely conditions are possible on ~3 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Humidity Minor
High humidity Measures: High humidity days (RH >=80%). Observed about 72% of days (22.3 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
22.3 days / month
- Share of days
- ~72% of days
- Upper edge
- Up to ~95% (P95)
Why this matters
High humidity is possible on ~22 days. Comfort and pace can drop quickly, so plan shorter outdoor blocks with air-conditioned backup stops.
Cloud Minor
Cloudy days Measures: Cloudy days (cloud cover >=60%). Observed about 60% of days (18.5 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
18.5 days / month
- Share of days
- ~60% of days
- Upper edge
- Up to ~100% (P95)
Why this matters
Cloudy skies are possible on ~19 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Rain Minor
Wet days Measures: Wet days (>=0.1mm). Observed about 41% of days (12.7 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
12.7 days / month
- Share of days
- ~41% of days
- Upper edge
- Up to ~28mm (P95)
Why this matters
Measurable rain is possible on ~13 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Cloud Minor
Mostly cloudy days Measures: Mostly cloudy days (cloud cover >=80%). Observed about 40% of days (12.3 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
12.3 days / month
- Share of days
- ~40% of days
- Upper edge
- Up to ~100% (P95)
Why this matters
Mostly cloudy skies are possible on ~12 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Rain Minor
Rainy hours Measures: Rain-hours signal (>=3h rain). Observed about 34% of days (10.4 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
10.4 days / month
- Share of days
- ~34% of days
- Upper edge
- Up to ~22h (P95)
Why this matters
Several rainy hours are possible on ~10 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Cold Minor
Cold nights Measures: Cold nights (min <=5C). Observed about 28% of days (8.7 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
8.7 days / month
- Share of days
- ~28% of days
- Upper edge
- Up to ~5°C (P95)
Why this matters
Cold nights are possible on ~9 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Rain Minor
Wet most of day Measures: Wet-most-of-day signal (>=6h rain). Observed about 27% of days (8.3 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
8.3 days / month
- Share of days
- ~27% of days
- Upper edge
- Up to ~22h (P95)
Why this matters
Wet-most-of-day conditions are possible on ~8 days. Outdoor plans can become unreliable, so keep an indoor backup and flexibility around start times.
Wind Minor
Gusty days Measures: Gusty days (>=40 km/h). Observed about 23% of days (7.3 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
7.3 days / month
- Share of days
- ~23% of days
- Upper edge
- Up to ~85km/h (P95)
Why this matters
Gusty conditions are possible on ~7 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Cloud Minor
Overcast days Measures: Overcast days (cloud cover >=95%). Observed about 20% of days (6.2 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
6.2 days / month
- Share of days
- ~20% of days
- Upper edge
- Up to ~100% (P95)
Why this matters
Overcast skies are possible on ~6 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Other Minor
Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data Measures: Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data. Observed about 8% of days (2.5 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
2.5 days / month
- Share of days
- ~8% of days
- Upper edge
- Up to ~97 (P95)
Why this matters
Low visibility proxy: same as fog-likely (RH ≥90% AND cloud ≥95%) — true visibility requires hourly visibility data is possible on ~3 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Cold Minor
Cold days Measures: Cold days (max <=10C). Observed about 5% of days (1.6 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
1.6 days / month
- Share of days
- ~5% of days
- Upper edge
- Up to ~10°C (P95)
Why this matters
Cold daytime conditions are possible on ~2 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Wind Minor
Breezy days Measures: Breezy days (mean wind >=25 km/h). Observed about 3% of days (0.9 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.9 days / month
- Share of days
- ~3% of days
- Upper edge
- Up to ~34km/h (P95)
Why this matters
Breezy conditions are possible on ~1 days. Exposed activities and transport links are more likely to be disrupted, so keep sheltered alternatives ready.
Cold Minor
Freezing nights Measures: Freezing nights (min <=0C). Observed about 1% of days (0.2 days/month) in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.2 days / month
- Share of days
- ~1% of days
- Upper edge
- Up to ~-0°C (P95)
Why this matters
Freezing nights are possible on ~0 days. Fixed-time outdoor plans are safer with a backup option and flexible timing.
Cold Minor
Cold snap run Measures: Cold snap runs (>=3 cold days). Observed about 0.2 days/month in January. Historical risk signal only, not a day-by-day forecast.
Likely frequency
0.2 days / month
- Share of days
- —
- Upper edge
- Up to ~10°C (P95)
Why this matters
Cold snap runs are possible on ~0 days. Long outdoor blocks become harder to sustain, so layer up and keep a warm indoor fallback nearby.
Travel planning FAQ
Frequently asked questions
Quick answers to the weather questions you ask the most.
Is January a good time to visit San Francisco?
Typical January days in San Francisco reach highs of 14°C (57°F) with nights around 7°C (45°F). It usually feels cool by day and cold after dark. It is among the wetter months, so it is wise to have some indoor backup plans or flexible activities.
What are temperatures like in January?
Daytime temperatures in January typically peak near 14°C (57°F), while nights drop to around 7°C (45°F). Expect cool afternoons and cold evenings.
How much does it rain in January?
Rainfall in January averages 126 mm (5.0 in) across roughly 12 days. Overall it is a quite rainy time of year, so a light rain jacket and waterproof shoes are very handy.
How many hours of daylight are there in January?
You can expect about 10 hours of daylight in January. Sunrise is typically around 07:21 and sunset near 17:15. Days are on the shorter side, so plan activities around limited daylight.
How strong is the sun in January?
UV levels are moderate (around 4); sunscreen and sunglasses are still a good idea.
Is it windy in January?
In January, average wind speeds are around 13 km/h (8 mph), with gusts on the windiest days reaching about 59 km/h (37 mph). On the ground, it is it can feel quite windy at times, particularly when weather systems move through.