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Contents
- The climate of Santa Rosa
- The best time to visit Santa Rosa
- The worst time to visit Santa Rosa
- Spring weather in Santa Rosa
- Summer weather in Santa Rosa
- Autumn weather in Santa Rosa
- Winter weather in Santa Rosa
- Weather in January
- Weather in February
- Weather in March
- Weather in April
- Weather in May
- Weather in June
- Weather in July
- Weather in August
- Weather in September
- Weather in October
- Weather in November
- Weather in December
- Frequently asked questions
- Average temperature
- Average pressure
- Average wind speed
- Average humidity
- Average rainfall
- Average rainfall days
- Average daylight
- Average sunshine
- Average sunshine days
- Average UV index
- Average cloud cover
- Average visibility
Set in a scenic valley, the Camarillo region of Santa Rosa, California, has great modern homes and is neared by scenic rugged mountain layouts
The climate of Santa Rosa
Nestled in the heart of the state's wine country, Santa Rosa experiences a warm Mediterranean climate classified as Csb according to the Köppen climate classification system. By parsing these conditions carefully, a pattern emerges across its annual weather cycles.
Temperature highs in Santa Rosa range from a mild 57.2°F (14°C) in the height of winter to a pleasant 79.7°F (26.5°C) in the peak of the summer season, revealing a moderate weather pattern throughout the year. The coldest monthly low falls to 41.9°F (5.5°C) during the wintertime while the warmest monthly low sits at 54.7°F (12.6°C) during the hottest peak periods in summer. These temperatures denote a moderate climate, devoid of extreme temperature fluctuations.
Santa Rosa's rainfall averages balance between 0.04" (1mm) during the lean season in July and August, spiking up to 2.64" (67mm) in February. The number of rainfall days, likewise, varies from 0.8 days in August and increases to 12.6 days in March. This suggests that the seasonality of rainfall aligns largely with the turn of the year into spring.
Another key parameter in Santa Rosa’s climate is sunshine. At its peak in July, residents enjoy up to an average of 14.5 daylight hours and 11.9 hours of sunshine, highlighting Santa Rosa's typically sunny summers. The shortest daylight period is experienced in December with 9.5 hours, leading to 5.7 hours of sunshine, delineating a noticeable but not drastic reduction in the winter months. Unsurprisingly, alongside this, the highest UV index is observed in June at a reading of 6, decreasing to as low as 3 in winter months.
The locality exhibits 36% cloud cover in January while the least cloud cover is reported in July, with only 9%. Correspondingly, wind speeds vary but not dramatically, with the fastest recorded winds appearing in May at 7.1mph (11.4km/h). Wind gusts mirror this pattern, peaking at 10.9mph (17.5km/h) in April and tapering down to 7.7mph (12.4km/h) in August.
Temperature highs in Santa Rosa range from a mild 57.2°F (14°C) in the height of winter to a pleasant 79.7°F (26.5°C) in the peak of the summer season, revealing a moderate weather pattern throughout the year. The coldest monthly low falls to 41.9°F (5.5°C) during the wintertime while the warmest monthly low sits at 54.7°F (12.6°C) during the hottest peak periods in summer. These temperatures denote a moderate climate, devoid of extreme temperature fluctuations.
Santa Rosa's rainfall averages balance between 0.04" (1mm) during the lean season in July and August, spiking up to 2.64" (67mm) in February. The number of rainfall days, likewise, varies from 0.8 days in August and increases to 12.6 days in March. This suggests that the seasonality of rainfall aligns largely with the turn of the year into spring.
Another key parameter in Santa Rosa’s climate is sunshine. At its peak in July, residents enjoy up to an average of 14.5 daylight hours and 11.9 hours of sunshine, highlighting Santa Rosa's typically sunny summers. The shortest daylight period is experienced in December with 9.5 hours, leading to 5.7 hours of sunshine, delineating a noticeable but not drastic reduction in the winter months. Unsurprisingly, alongside this, the highest UV index is observed in June at a reading of 6, decreasing to as low as 3 in winter months.
The locality exhibits 36% cloud cover in January while the least cloud cover is reported in July, with only 9%. Correspondingly, wind speeds vary but not dramatically, with the fastest recorded winds appearing in May at 7.1mph (11.4km/h). Wind gusts mirror this pattern, peaking at 10.9mph (17.5km/h) in April and tapering down to 7.7mph (12.4km/h) in August.
The best time to visit Santa Rosa
Considering the variety of weather parameters, the best time to visit Santa Rosa would arguably be from end of Spring to early Fall, between May and October. The charm of this period lies in the long daylight hours and abundant sunshine, which peak between June and August. Minimal rainfall, along with moderate temperatures averaging between 64.9°F (18.3°C) and 79.3°F (26.3°C) during day and from 45.5°F (7.5°C) to 54.7°F (12.6°C) at night, provide the perfect conditions for exploring the wineries and nature reserves in the region.
The worst time to visit Santa Rosa
Visitors looking to avoid the less favourable weather conditions in Santa Rosa should steer clear of late winter to early spring. Between February and March, the city experiences the highest rainfall, with up to 12.6 days of rain and an average of 2.64" (67mm) falling in February. While the temperatures during this time are not particularly extreme, ranging on average from 42.8°F (6°C) to 60.4°F (15.8°C), the wet conditions could be uncomfortable for outdoor activities.
Spring weather in Santa Rosa
As March rolls into April and May, Spring announces its arrival in Santa Rosa with an appreciable decline in rainfall. The city experiences over 13.2 daylight hours by April, giving residents and visitors more time to soak up the abundant sunshine, which exceeds 10 hours per day. Average highs during this time start from 60.4°F (15.8°C) in March and climb to 69.1°F (20.6°C) by May, while lows gradually increase from 43.5°F (6.4°C) to 48.6°F (9.2°C).
Summer weather in Santa Rosa
Summers in Santa Rosa are largely dry and sunny, with the least rainfall recorded and only an average of 1.5 to 1.9 days of rain, from June to August. Day temperatures rise to highs between 76.3°F (24.6°C) and 79.7°F (26.5°C), while nighttime temperatures range comfortably from 53.1°F (11.7°C) to 54.7°F (12.6°C). These months see more than 14 daylight hours per day, and Santa Rosa basks under almost 12 hours of daily sunshine.
Autumn weather in Santa Rosa
The Autumn season in Santa Rosa, spanning September to November, is characterized by a gradual cooling of temperatures, with average highs decreasing from 79°F (26.1°C) to 63.1°F (17.3°C), and lows reducing from 54.7°F (12.6°C) down to 46°F (7.8°C). Rainfall begins to show a slight increase going from 0.12" (3mm) in September to 1.02" (26mm) in November. Sunshine hours per day and daylight hours slowly start to decrease to prepare for winter.
Winter weather in Santa Rosa
Winter in Santa Rosa does not see severe chilling temperatures as some might expect. In fact, December's temperatures range from 41.9°F (5.5°C) during the coolest nights to 55.6°F (13.1°C) at daytime's peak. Rainfall significantly increases during this season, receiving about over 2" (51mm) in December and peaking in February at 2.64" (67mm). With daylight and sunshine hours reducing to their annual lows, the overall wintertime climate might feel colder due to the combined effect of increased humidity, higher cloud cover, and prevailing winds.
Weather in January
In Santa Rosa, California, January kicks off with lower temperatures than the preceding December. The climate in January tends to favor more humidity and a significant amount of rainfall, with the rain gauge reading an average of 2.01" (51mm) during this month. Weather in January »
Weather in February
Transitioning from January to February, Santa Rosa sees a slight uptick in temperatures, though the weather remains within the realm of winter characteristics. February experiences marginally lower rainfall and fewer rainy days than January, but relative humidity remains constant. Weather in February »
Weather in March
March signifies a subtle shift towards spring in Santa Rosa, California. The highest rainfall can be observed during March, a total of 2.01" (51mm), interspersed over 12.6 days. Despite the increase in rain, temperature trends align with the approach of spring, exhibiting a subtle rise from the February readings. Weather in March »
Weather in April
In comparison to March, April displays obvious signs of spring. A perceptible decrease in rainfall coupled with an increase in daylight hours sets the stage for the warmer months ahead in Santa Rosa. The increase in temperature is accompanied by a general decrease in humidity. Weather in April »
Weather in May
In Santa Rosa, May ushers in the warmer temperatures associated with late spring and early summer. The notable decrease in rainfall, down to 0.55" (14mm), is indicative of the drier season ahead. Also, the rise in temperature reflects the changing seasons in a subtle, climatic transition. Weather in May »
Weather in June
June in Santa Rosa is generally marked by warmer weather, leaning towards typical summer conditions. Interestingly, June witnesses the longest daylight hours at 14.8, offering ample time for outdoor activities. The rise in UV index suggests stronger sunlight, indicating the need for sun protection. Weather in June »
Weather in July
July in Santa Rosa, stepping into the depth of summer, records the highest temperatures, reaching up to 79.3°F (26.3°C). This hot month showcases declining rainfall and less cloud cover compared to the preceding June, thereby cementing the grip of the summer season. Weather in July »
Weather in August
As the final month of summer, August in Santa Rosa is marked by warm temperatures comparable to July. The almost negligible rainfall of 0.04" (1mm) further emphasizes the arid conditions. Furthermore, the fewest cloudy days in the year are noticed during August, emphasizing clear skies and plenty of sunshine. Weather in August »
Weather in September
In Santa Rosa, September transitions from summer to fall with temperatures cooling down moderately from August. The slight increase in rainfall compared to the bone-dry summer months also nudges the weather towards fall. The steady decrease in daylight hours continues through September, indicating the passage of seasons. Weather in September »
Weather in October
October captures the essence of fall in Santa Rosa with significantly cooler conditions compared to September. A continuous trend of increasing rainfall and decreasing daylight hours signals the deepening fall season. Following the weather pattern, the temperature keeps dropping, preparing the environment for the incoming winter. Weather in October »
Weather in November
November in Santa Rosa experiences further drops in temperature and daylight hours, leading the transition from fall into early winter. With the highest post-summer rainfall of 1.02" (26mm), November underscores the shift towards the cold season. Weather in November »
Weather in December
Closing out the year, December in Santa Rosa epitomizes the winter season in the city. Though temperatures and daylight hours fall noticeably from November levels, the winter here is relatively mild and temperate. Correspondingly, the increase in rainfall from 1.02" (26mm) to 2.24" (57mm) in December highlights the winter imprint. Weather in December »
Updated: Feb 9, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How many days does it rain in Santa Rosa?
Throughout the year, in Santa Rosa, there are 72.8 rainfall days, and 12.01" (305mm) of precipitation is accumulated.
When is the lowest UV index in Santa Rosa?
January, February, November and December, with an average maximum UV index of 3, are months with the lowest UV index.
What is the wettest month in Santa Rosa?
February is the month with the most rainfall. Rain falls for 9.1 days and accumulates 2.64" (67mm) of precipitation.
What is the most humid month in Santa Rosa?
The most humid month in Santa Rosa is March, with an average relative humidity of 77%.
When is Daylight Saving Time (DST) in Santa Rosa?
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from PST to PDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from PDT to PST.
When are the longest days in Santa Rosa?
June has the longest days of the year in Santa Rosa, California, with an average of 14h and 48min of daylight.
When is the highest UV index in Santa Rosa?
June is the month with the highest UV index, with an average maximum UV index of 6.
What is the driest month in Santa Rosa?
July and August are months with the least rain when the rain falls for 1.5 days and typically aggregates up to 0.04" (1mm) of rain.
What month has the most sunshine in Santa Rosa?
The month with the most sunshine is July, with an average of 11.9h of sunshine.
What is the warmest month in Santa Rosa?
In Santa Rosa, August records the average highest temperatures, peaking at 79.7°F (26.5°C) and reaching a low of 54.7°F (12.6°C).
What is the least humid month in Santa Rosa?
The least humid month is September, with an average relative humidity of 63%.
What is the coldest month in Santa Rosa?
The lowest temperatures are recorded in December, with averages reaching a high of 55.6°F (13.1°C) and a low of 41.9°F (5.5°C).
What is the month with the shortest days in Santa Rosa?
December has the shortest days of the year in Santa Rosa, with an average of 9h and 30min of daylight.
What is the month with the least sunshine in Santa Rosa?
With an average of 5.7h of sunshine, December has the least sunshine of the year in Santa Rosa.
Average temperature
Santa Rosa, CA
The warmest month (with the highest average high temperature) is August (79.7°F).
The month with the lowest average high temperature is December (55.6°F).
The months with the highest average low temperature are August and September (54.7°F).
The coldest month (with the lowest average low temperature) is December (41.9°F).
Average pressure
Santa Rosa, CA
- Average pressure in January:
30.13"Hg - Average pressure in February:
30.07"Hg - Average pressure in March:
30.06"Hg - Average pressure in April:
30.03"Hg - Average pressure in May:
29.98"Hg - Average pressure in June:
29.92"Hg
- Average pressure in July:
29.93"Hg - Average pressure in August:
29.92"Hg - Average pressure in September:
29.92"Hg - Average pressure in October:
29.99"Hg - Average pressure in November:
30.07"Hg - Average pressure in December:
30.1"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).
Average wind speed
Santa Rosa, CA
- Average wind speed in January:
5.2mph - Average wind speed in February:
6mph - Average wind speed in March:
6.5mph - Average wind speed in April:
7mph - Average wind speed in May:
7.1mph - Average wind speed in June:
6.8mph
- Average wind speed in July:
5.5mph - Average wind speed in August:
5.2mph - Average wind speed in September:
5.2mph - Average wind speed in October:
5.1mph - Average wind speed in November:
4.9mph - Average wind speed in December:
5.2mph
The windiest month (with the highest average wind speed) is May (7.1mph).
The calmest month (with the lowest average wind speed) is November (4.9mph).
Average humidity
Santa Rosa, CA
The month with the highest relative humidity is March (77%).
The month with the lowest relative humidity is September (63%).
Average rainfall
Santa Rosa, CA
- Average rainfall in January:
2.01" - Average rainfall in February:
2.64" - Average rainfall in March:
2.01" - Average rainfall in April:
0.55" - Average rainfall in May:
0.55" - Average rainfall in June:
0.12"
- Average rainfall in July:
0.04" - Average rainfall in August:
0.04" - Average rainfall in September:
0.12" - Average rainfall in October:
0.67" - Average rainfall in November:
1.02" - Average rainfall in December:
2.24"
The wettest month (with the highest rainfall) is February (2.64").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days
Santa Rosa, CA
- Average rainfall days in January:
10 days - Average rainfall days in February:
9.1 days - Average rainfall days in March:
12.6 days - Average rainfall days in April:
7 days - Average rainfall days in May:
5.3 days - Average rainfall days in June:
1.9 days
- Average rainfall days in July:
1.5 days - Average rainfall days in August:
0.8 days - Average rainfall days in September:
2.8 days - Average rainfall days in October:
4.8 days - Average rainfall days in November:
6.5 days - Average rainfall days in December:
10.5 days
The month with the highest number of rainy days is March (12.6 days).
The month with the least rainy days is August (0.8 days).
Average daylight / Average sunshine
Santa Rosa, CA
- Average daylight in January:
9h and 5min - Average daylight in February:
10h and 5min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 1min - Average daylight in May:
14h and 2min - Average daylight in June:
14h and 5min
- Average daylight in July:
14h and 3min - Average daylight in August:
13h and 4min - Average daylight in September:
12h and 2min - Average daylight in October:
11h and 1min - Average daylight in November:
10h and 1min - Average daylight in December:
9h and 3min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in January:
5h and 5min - Average sunshine in February:
6h and 1min - Average sunshine in March:
7h and 3min - Average sunshine in April:
10h and 1min - Average sunshine in May:
10h and 3min - Average sunshine in June:
11h and 4min
- Average sunshine in July:
11h and 5min - Average sunshine in August:
11h and 5min - Average sunshine in September:
11h and 0min - Average sunshine in October:
6h and 5min - Average sunshine in November:
6h and 3min - Average sunshine in December:
5h and 4min
The month with the most sunshine is July (Average sunshine: 11h and 54min).
The month with the least sunshine is December (Average sunshine: 5h and 42min).
Average sunshine days
Santa Rosa, CA
- Average sunshine days in January:
19.9 days - Average sunshine days in February:
18.1 days - Average sunshine days in March:
17.1 days - Average sunshine days in April:
21.8 days - Average sunshine days in May:
23.4 days - Average sunshine days in June:
26.5 days
- Average sunshine days in July:
27.2 days - Average sunshine days in August:
27.1 days - Average sunshine days in September:
26.5 days - Average sunshine days in October:
24.8 days - Average sunshine days in November:
21.9 days - Average sunshine days in December:
19.5 days
The month with the most sunshine days is July (27.2 days).
The month with the least sunshine days is March (17.1 days).
Average UV index
Santa Rosa, CA
The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover
Santa Rosa, CA
The month with the most cloud cover is March (Cloud cover 39).
The month with the least cloud cover is July (Cloud cover 9).
Average visibility
Santa Rosa, CA
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Santa Rosa, California, USA
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