May weather forecast
Hillsborough, CA

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Weather in May

The last month of the spring, May, is another refreshing month in Hillsborough, California, with an average temperature fluctuating between 63.1°F (17.3°C) and 50.5°F (10.3°C).

Temperature

The shift from April to May is characterized by an average high-temperature of a still enjoyable 63.1°F (17.3°C), not significantly different from the 61.3°F (16.3°C) of April. Hillsborough, during May nights, observes an average temperature of 50.5°F (10.3°C).

Humidity

In Hillsborough, the average relative humidity in May is 76%.

Rainfall

In May, the rain falls for 5.7 days. Throughout May, 0.63" (16mm) of precipitation is accumulated. Throughout the year, there are 81.5 rainfall days, and 12.8" (325mm) of precipitation is accumulated.

Daylight

The average length of the day in May is 14h and 13min.
On the first day of May, sunrise is at 6:12 am and sunset at 8:00 pm. On the last day of the month, sunrise is at 5:49 am and sunset at 8:24 pm PDT.

Sunshine

In May, the average sunshine is 10.5h.

UV index

In May, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for the average person.
Note: In May, the average maximum UV index of 4 translates into the following recommendations:
Ensure safety - Recommendations to avert sunburn are presented. The most potent solar radiation is around mid-day, so one should minimize exposure to direct sunlight during this period. For holistic sun protection encompassing the eyes, ears, face, and neck, a wide-brim hat is key.
Updated: Aug 26, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the temperatures in May?

In Hillsborough, 63.1°F (17.3°C) is the average high-temperature and 50.5°F (10.3°C) is the average low-temperature during May.

What is the average humidity in May?

The average relative humidity in May is 76%.

How many days does it rain in May?

In Hillsborough, in May, it is raining for 5.7 days, with typically 0.63" (16mm) of accumulated precipitation.

How many hours of daylight does Hillsborough have in May?

In May, the average day length in Hillsborough is 14h and 13min.

What time are sunrise and sunset in May?

In May, on the first day of the month, sunrise is at 6:12 am and sunset at 8:00 pm. On the last day of the month, in Hillsborough, California, sunrise is at 5:49 am and sunset at 8:24 pm PDT.

How long on average sun shines in May?

The average sunshine duration in May is 10.5h.

What is the UV index intensity in May?

In Hillsborough, the average daily maximum UV index in May is 4. A UV Index reading of 3 to 5 represents a moderate health threat from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in May
Hillsborough, CA

Average temperature in May - Hillsborough, CA
  • Average high temperature in May: 63.1°F

The warmest month (with the highest average high temperature) is September (70.2°F).
The month with the lowest average high temperature is December (55.6°F).

  • Average low temperature in May: 50.5°F

The month with the highest average low temperature is September (56.8°F).
The coldest month (with the lowest average low temperature) is January (47.5°F).

Average pressure in May
Hillsborough, CA

Average pressure in May - Hillsborough, CA
  • Average pressure in May: 29.98"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is September (29.92"Hg).

Average wind speed in May
Hillsborough, CA

Average wind speed in May - Hillsborough, CA
  • Average wind speed in May: 8.2mph

The windiest month (with the highest average wind speed) is April (8.3mph).
The calmest month (with the lowest average wind speed) is September (6.1mph).

Average humidity in May
Hillsborough, CA

Average humidity in May - Hillsborough, CA
  • Average humidity in May: 76%

The month with the highest relative humidity is August (78%).
The month with the lowest relative humidity is October (70%).

Average rainfall in May
Hillsborough, CA

Average rainfall in May - Hillsborough, CA
  • Average rainfall in May: 0.63"

The wettest month (with the highest rainfall) is February (2.44").
The driest month (with the least rainfall) is July (0.08").

Average rainfall days in May
Hillsborough, CA

Average rainfall days in May - Hillsborough, CA
  • Average rainfall days in May: 5.7 days

The month with the highest number of rainy days is March (12.8 days).
The months with the least rainy days are June and July (2.4 days).

Average daylight in May /
Average sunshine in May
Hillsborough, CA

Average daylight in May / Average sunshine in May - Hillsborough, CA
  • Average daylight in May: 14h and 1min

The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).

  • Average sunshine in May: 10h and 3min

The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).

Average sunshine days in May
Hillsborough, CA

Average sunshine days in May - Hillsborough, CA
  • Average sunshine days in May: 22.1 days

The month with the most sunshine days is July (24.6 days).
The month with the least sunshine days is March (16.3 days).

Average UV index in May
Hillsborough, CA

Average UV index in May - Hillsborough, CA
  • Average UV index in May: 4

The months with the highest UV index are June, July, August and September (UV index 5).
The months with the lowest UV index are February and December (UV index 3).

Average cloud cover in May
Hillsborough, CA

Average cloud cover in May - Hillsborough, CA
  • Average cloud cover in May: 27

The month with the most cloud cover is March (Cloud cover 36).
The months with the least cloud cover are July and September (Cloud cover 15).

Average visibility in May
Hillsborough, CA

Average visibility in May - Hillsborough, CA
  • Average visibility in May: 6mi

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).

Hillsborough, California, USA

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