May weather forecast
Ontario, CA

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The luxurious residential estate in Ontario, California, with a scenic background of a hilly landscape
The luxurious residential estate in Ontario, California, with a scenic background of a hilly landscape

Weather in May

May, the last month of the spring in Ontario, is a moderately hot month, with temperature in the range of an average high of 76.6°F (24.8°C) and an average low of 53.6°F (12°C).

Temperature

Ontario's average high-temperature in May is a moderately hot 76.6°F (24.8°C), indicating a subtle variation from April. A steep decline to a cool 53.6°F (12°C) characterizes the May nights.

Humidity

March and May, with an average relative humidity of 54%, are the most humid months in Ontario.

Rainfall

In Ontario, during May, the rain falls for 3.8 days and regularly aggregates up to 0.24" (6mm) of precipitation. Throughout the year, in Ontario, there are 49.6 rainfall days, and 7.8" (198mm) of precipitation is accumulated.

Snowfall

In Ontario, snow does not fall in January, March through December.

Daylight

The average length of the day in May is 13h and 57min.
On the first day of the month, sunrise is at 6:00 am and sunset at 7:34 pm. On the last day of May, in Ontario, sunrise is at 5:40 am and sunset at 7:56 pm PDT.

Sunshine

The average sunshine in May in Ontario is 11.8h.

UV index

In Ontario, the average daily maximum UV index in May is 6. A UV Index reading of 6 to 7 represents a high threat to health from exposure to the Sun's UV radiation for average individuals.
Note: A typical high UV index of 6 in May suggests the following recommendations:
Stand by precautions and apply sun safety measures. Evading sunburn is of great importance. Stay in the shade and avoid direct Sun exposure from 10 a.m. to 4 p.m., a time when UV radiation is at its strongest, and remember that parasols or canopies do not offer full protection. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage.
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Frequently asked questions

What are the temperatures in Ontario in May?

The high-temperature, in May, in Ontario, is 76.6°F (24.8°C), while the low-temperature averages to 53.6°F (12°C).

What are the most humid months in Ontario?

March and May, with an average relative humidity of 54%, are most humid months in Ontario.

What is the average humidity in May in Ontario?

In May, the average relative humidity in Ontario, California, is 54%.

How much does it rain in Ontario in May?

In Ontario, during May, the rain falls for 3.8 days and regularly aggregates up to 0.24" (6mm) of precipitation.

When it does not snow in Ontario?

In Ontario, California, snow does not fall in January, March through December.

What is the average length of the day in May in Ontario?

The average day length in May is 13h and 57min.

What time are sunrise and sunset in May in Ontario?

In May, on the first day of the month, sunrise is at 6:00 am and sunset at 7:34 pm. On the last day of the month, in Ontario, sunrise is at 5:40 am and sunset at 7:56 pm PDT.

How many hours of sunshine does Ontario have in May?

In Ontario, California, the average sunshine duration in May is 11.8h.

What is the UV index reading in May in Ontario?

The average daily maximum UV index in May in Ontario is 6. A UV Index reading of 6 to 7 represents a high health risk from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in May
Ontario, CA

Average temperature in May - Ontario, CA
  • Average high temperature in May: 76.6°F

The warmest month (with the highest average high temperature) is August (91°F).
The month with the lowest average high temperature is December (62.1°F).

  • Average low temperature in May: 53.6°F

The month with the highest average low temperature is August (65.8°F).
The coldest month (with the lowest average low temperature) is December (45.5°F).

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Average pressure in May
Ontario, CA

Average pressure in May - Ontario, CA
  • Average pressure in May: 29.91"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).

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Average wind speed in May
Ontario, CA

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

The windiest months (with the highest average wind speed) are April and May (5.8mph).
The calmest month (with the lowest average wind speed) is September (4.4mph).

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Average humidity in May
Ontario, CA

Average humidity in May - Ontario, CA
  • Average humidity in May: 54%

The months with the highest relative humidity are March and May (54%).
The month with the lowest relative humidity is August (42%).

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Average rainfall in May
Ontario, CA

Average rainfall in May - Ontario, CA
  • Average rainfall in May: 0.24"

The wettest month (with the highest rainfall) is February (1.77").
The driest month (with the least rainfall) is June (0.04").

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Average rainfall days in May
Ontario, CA

Average rainfall days in May - Ontario, CA
  • Average rainfall days in May: 3.8 days

The month with the highest number of rainy days is March (7.1 days).
The month with the least rainy days is June (1.2 days).

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Average snowfall days in May
Ontario, CA

Average snowfall days in May - Ontario, CA
  • Average snowfall days in May: 0 days

The month with the highest number of snowfall days is February (0.1 days).
The months with the least snowfall days are January, March, April, May, June, July, August, September, October, November and December (0 days).

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

Average daylight in May / Average sunshine in May - Ontario, CA
  • Average daylight in May: 13h and 5min

The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).

  • Average sunshine in May: 11h and 5min

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The months with the least sunshine are February and December (Average sunshine: 6h and 54min).

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Average sunshine days in May
Ontario, CA

Average sunshine days in May - Ontario, CA
  • Average sunshine days in May: 26 days

The month with the most sunshine days is June (28.2 days).
The month with the least sunshine days is February (21.5 days).

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Average UV index in May
Ontario, CA

Average UV index in May - Ontario, CA
  • Average UV index in May: 6

The months with the highest UV index are July and August (UV index 7).
The month with the lowest UV index is December (UV index 3).

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Average cloud cover in May
Ontario, CA

Average cloud cover in May - Ontario, CA
  • Average cloud cover in May: 13

The month with the most cloud cover is December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 5).

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Average visibility in May
Ontario, CA

Average visibility in May - Ontario, 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).

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Ontario, California, USA

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