May weather forecastCosta Mesa, CA
May
Weather in May
The last month of the spring, May, is another comfortable month in Costa Mesa, California, with temperature in the range of an average low of 56.8°F (13.8°C) and an average high of 67.6°F (19.8°C).Temperature
Costa Mesa experiences a transition to a still comfortable 67.6°F (19.8°C) in average high-temperatures with the arrival of May, not greatly differing from April's 66.6°F (19.2°C). In the month of May, Costa Mesa witnesses a consistent average low-temperature of 56.8°F (13.8°C).Humidity
The average relative humidity in May in Costa Mesa, California, is 72%.Rainfall
In Costa Mesa, California, in May, during 3.4 rainfall days, 0.12" (3mm) of precipitation is typically accumulated. Throughout the year, there are 50.7 rainfall days, and 3.74" (95mm) of precipitation is accumulated.Daylight
In Costa Mesa, California, the average length of the day in May is 13h and 55min.On the first day of the month, sunrise is at 6:02 am and sunset at 7:35 pm. On the last day of May, in Costa Mesa, sunrise is at 5:42 am and sunset at 7:56 pm PDT.
Sunshine
The average sunshine in May is 11h.UV index
In May, the average daily maximum UV index in Costa Mesa, California, is 5. A UV Index reading of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for ordinary individuals.Note: The UV index of 5 during May translates into the following guidance:
Exercise caution. Those with pale skin may experience burns in less than half an hour. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in May
Costa Mesa, CA
- Average high temperature in May: 67.6°F
The warmest month (with the highest average high temperature) is August (76.6°F).
The month with the lowest average high temperature is December (62.4°F).
- Average low temperature in May: 56.8°F
The month with the highest average low temperature is August (64.9°F).
The coldest month (with the lowest average low temperature) is February (52.3°F).
Average pressure in May
Costa Mesa, CA
- Average pressure in May: 29.93"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The months with the lowest atmospheric pressure are June and September (29.89"Hg).
Average wind speed in May
Costa Mesa, CA
- Average wind speed in May: 6.5mph
The windiest month (with the highest average wind speed) is April (6.6mph).
The calmest month (with the lowest average wind speed) is October (5.2mph).
Average humidity in May
Costa Mesa, CA
- Average humidity in May: 72%
The month with the highest relative humidity is June (74%).
The month with the lowest relative humidity is November (59%).
Average rainfall in May
Costa Mesa, CA
- Average rainfall in May: 0.12"
The wettest month (with the highest rainfall) is December (0.79").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in May
Costa Mesa, CA
- Average rainfall days in May: 3.4 days
The month with the highest number of rainy days is March (6.6 days).
The month with the least rainy days is June (1.6 days).
Average daylight in May /
Average sunshine in May
Costa Mesa, CA
- Average daylight in May: 13h and 54min
The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 10h and 0min).
- Average sunshine in May: 11h and 0min
The month with the most sunshine is August (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 6h and 36min).
Average sunshine days in May
Costa Mesa, CA
- Average sunshine days in May: 23.4 days
The month with the most sunshine days is June (26.5 days).
The month with the least sunshine days is February (20.5 days).
Average UV index in May
Costa Mesa, CA
- Average UV index in May: 5
The months with the highest UV index are July, August and September (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 4).
Average cloud cover in May
Costa Mesa, CA
- Average cloud cover in May: 21
The months with the most cloud cover are March and December (Cloud cover 24).
The month with the least cloud cover is August (Cloud cover 8).
Average visibility in May
Costa Mesa, 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).





