May weather forecast
Saint Helena, CA

Share

Weather in May

The last month of the spring, May, is a warm month in Saint Helena, California, with an average temperature varying between 46.9°F (8.3°C) and 74.1°F (23.4°C).

Temperature

May sees a marginal temperature increase, moving from an agreeable 68°F (20°C) in April to a warm 74.1°F (23.4°C). The May nights bear witness to a significant drop from the daytime highs, settling at an average temperature of 46.9°F (8.3°C).

Humidity

The average relative humidity in May is 64%.

Rainfall

In Saint Helena, during May, the rain falls for 5.7 days and regularly aggregates up to 0.87" (22mm) of precipitation. Throughout the year, there are 76.2 rainfall days, and 16.93" (430mm) of precipitation is accumulated.

Snowfall

January, February, April through December are months without snowfall.

Daylight

The average length of the day in May in Saint Helena is 14h and 17min.
On the first day of the month, sunrise is at 6:11 am and sunset at 8:02 pm. On the last day of May, sunrise is at 5:47 am and sunset at 8:27 pm PDT.

Sunshine

The average sunshine in May in Saint Helena is 10.2h.

UV index

The average daily maximum UV index in May in Saint Helena is 5. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for ordinary individuals.
Note: In May, a regular UV index of 5 translates into these guidelines:
Take necessary precautions - Suggestions to elude sunburn are provided. The Sun is at its harshest during midday; protect yourself by staying in shaded areas and minimizing exposure. For holistic sun protection encompassing the eyes, ears, face, and neck, a wide-brim hat is key.
[Resources]

Frequently asked questions

What are May temperatures in Saint Helena?

In Saint Helena, in May, the average high-temperature is 74.1°F (23.4°C), and the average low-temperature is 46.9°F (8.3°C).

What is the average humidity in May in Saint Helena?

In Saint Helena, California, the average relative humidity in May is 64%.

How many days does it rain in May in Saint Helena?

In May, in Saint Helena, the rain falls for 5.7 days. Throughout May, 0.87" (22mm) of precipitation is accumulated.

When it does not snow in Saint Helena?

January, February, April through December are months without snowfall in Saint Helena.

How many hours of daylight does Saint Helena have in May?

In Saint Helena, the average day length in May is 14h and 17min.

When are sunrise and sunset in May in Saint Helena?

In May, on the first day of the month, sunrise is at 6:11 am and sunset at 8:02 pm. On the last day of the month, sunrise is at 5:47 am and sunset at 8:27 pm PDT.

How many hours of sunshine does Saint Helena have in May?

In Saint Helena, California, the average sunshine duration in May is 10.2h.

What is the UV index reading in May in Saint Helena?

The average daily maximum UV index in May in Saint Helena is 5. 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 snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in May
Saint Helena, CA

Average temperature in May - Saint Helena, CA
  • Average high temperature in May: 74.1°F

The warmest month (with the highest average high temperature) is July (88.3°F).
The month with the lowest average high temperature is December (54.5°F).

  • Average low temperature in May: 46.9°F

The month with the highest average low temperature is September (54.3°F).
The coldest month (with the lowest average low temperature) is December (39.6°F).

[Resources]

Average pressure in May
Saint Helena, CA

Average pressure in May - Saint Helena, CA
  • Average pressure in May: 29.97"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.91"Hg).

[Resources]

Average wind speed in May
Saint Helena, CA

Average wind speed in May - Saint Helena, CA
  • Average wind speed in May: 5.8mph

The windiest month (with the highest average wind speed) is May (5.8mph).
The calmest month (with the lowest average wind speed) is November (4.3mph).

[Resources]

Average humidity in May
Saint Helena, CA

Average humidity in May - Saint Helena, CA
  • Average humidity in May: 64%

The month with the highest relative humidity is March (76%).
The month with the lowest relative humidity is September (53%).

[Resources]

Average rainfall in May
Saint Helena, CA

Average rainfall in May - Saint Helena, CA
  • Average rainfall in May: 0.87"

The wettest month (with the highest rainfall) is February (3.7").
The driest month (with the least rainfall) is July (0").

[Resources]

Average rainfall days in May
Saint Helena, CA

Average rainfall days in May - Saint Helena, CA
  • Average rainfall days in May: 5.7 days

The month with the highest number of rainy days is March (13.5 days).
The month with the least rainy days is August (0.3 days).

[Resources]

Average snowfall in May
Saint Helena, CA

Average snowfall in May - Saint Helena, CA
  • Average snowfall in May: 0"

The month with the highest snowfall is March (0.04").
The months with the least snowfall are January, February, April, May, June, July, August, September, October, November and December (0").

[Resources]

Average snowfall days in May
Saint Helena, CA

Average snowfall days in May - Saint Helena, CA
  • Average snowfall days in May: 0 days

The month with the highest number of snowfall days is March (0.2 days).
The months with the least snowfall days are January, February, April, May, June, July, August, September, October, November and December (0 days).

[Resources]

Average daylight in May /
Average sunshine in May
Saint Helena, CA

Average daylight in May / Average sunshine in May - Saint Helena, CA
  • Average daylight in May: 14h and 2min

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 May: 10h and 1min

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 18min).

[Resources]

Average sunshine days in May
Saint Helena, CA

Average sunshine days in May - Saint Helena, CA
  • Average sunshine days in May: 24.2 days

The month with the most sunshine days is July (30 days).
The month with the least sunshine days is March (15.9 days).

[Resources]

Average UV index in May
Saint Helena, CA

Average UV index in May - Saint Helena, CA
  • Average UV index in May: 5

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).

[Resources]

Average cloud cover in May
Saint Helena, CA

Average cloud cover in May - Saint Helena, CA
  • Average cloud cover in May: 29

The month with the most cloud cover is March (Cloud cover 44).
The month with the least cloud cover is July (Cloud cover 7).

[Resources]

Average visibility in May
Saint Helena, CA

Average visibility in May - Saint Helena, CA
  • Average visibility in May: 6mi

The months with the highest visibility are February, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January and March (5mi).

[Resources]

Saint Helena, California, USA

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location