Millbrae, United States — Weather in May 2027

Climate Overview

Millbrae, United States in May has mild conditions, with highs averaging 18.6°C (65°F) and noticeably cooler mornings. Rain is rare, falling on about 3 days this month. Sea temperature stays cool at 13.8°C (57°F).

This month falls at the end of Spring.

Temperatures remain fairly steady throughout May, with daily highs around 19°C (66°F).

Rainfall is heaviest during the middle of the month, while the last third tends to be drier.

Expect around 12.0h of sunshine at the start of May, increasing to 12.9h by the end.

The warmest days tend to fall around the 31th, averaging 19.8°C (68°F).

Compared to April, this month is about 2°C warmer with 2 fewer rainy days. Temperatures will rise further into June.

Monthly May Averages

Temperature

19°C / 11°C

Feels Like

19°C / 10°C

Rain

3 days · 18 mm

Sunshine

12.5h / day

Humidity

77% — Humid

Wind

16 km/h

Wind Direction

W (265°)

Gusts

41 km/h

Daylight

14.2 h

Cloud Cover

50%

Clear Sky Days

6.4

UV Index

7.9 — Very High

Sea Temperature

14°C

Dew Point

11°C — Comfortable

Moon Phase

Waxing Gibbous · 66%

Climate Charts

Daily averages based on historical data (2016–2025)

Daily Temperature

HighLow

Daily Precipitation

Rainfall

Daily Sunshine

Sunshine

Daily Wind Speed

Wind Speed

Sun Position

Sunrise 06:01

Daylight 14.2h

Sunset 20:13

Compare Months

3days (18 mm) Excellent

0days (1 mm) Excellent

0days (0 mm) Excellent

0days (1 mm) Excellent

1days (3 mm) Excellent

2days (24 mm) Excellent

Month	Temp	Feels Like	Rain	Sun	Humidity	UV	Status	Details
January	14°C / 8°C	13°C / 7°C	10days (112 mm) Wet	6.9h Fair	84% Humid	3 Moderate	Fair	View Details
February	15°C / 8°C	14°C / 6°C	7days (90 mm) Good	8.5h Good	80% Humid	3.8 Moderate	Fair	View Details
March	15°C / 9°C	14°C / 7°C	12days (99 mm) Wet	9.4h Good	80% Humid	5.6 High	Good	View Details
April	17°C / 10°C	17°C / 9°C	5days (30 mm) Good	11h Excellent	78% Humid	6.9 High	Good	View Details
May	19°C / 11°C	19°C / 10°C	3days (18 mm) Excellent	12.5h Excellent	77% Humid	7.9 Very High	Good	View Details
June	21°C / 13°C	22°C / 12°C	0days (1 mm) Excellent	13.3h Excellent	76% Humid	8.2 Very High	Excellent	View Details
July	21°C / 14°C	23°C / 13°C	0days (0 mm) Excellent	13.1h Excellent	79% Humid	8.2 Very High	Excellent	View Details
August best	22°C / 15°C	24°C / 15°C	0days (1 mm) Excellent	12.4h Excellent	79% Humid	7.6 Very High	Excellent	View Details
September best	23°C / 15°C	24°C / 15°C	1days (3 mm) Excellent	11.3h Excellent	78% Humid	6.4 High	Excellent	View Details
October best	22°C / 14°C	21°C / 13°C	2days (24 mm) Excellent	9.6h Good	75% Muggy	5 Moderate	Excellent	View Details
November	17°C / 11°C	16°C / 10°C	6days (54 mm) Good	8.1h Good	80% Humid	3.4 Moderate	Good	View Details
December	15°C / 9°C	13°C / 7°C	9days (98 mm) Wet	6.7h Fair	84% Humid	2.7 Moderate	Good	View Details

What to Wear

Dress in layers — a mix of long sleeves, light sweaters, and a versatile jacket works best for changeable conditions.

Packing List

Warm evening layerComfortable walking shoes

Frequently Asked Questions

Expand all

Is May a good time to visit Millbrae?

May is typically good for visiting Millbrae, with average highs of 19°C (65°F) and around 3 rainy days. Millbrae, United States in May has mild conditions, with highs averaging 18.6°C (65°F) and noticeably cooler mornings. R

Does it rain a lot in Millbrae in May?

Millbrae typically sees around 3 rainy days in May with 18 mm (0.7 in) of total rainfall. An umbrella should suffice.

Does it get cold at night in Millbrae in May?

Nights in Millbrae during May are cool at around 11°C (52°F). Bring a jacket or sweater for evenings.

What should I pack for Millbrae in May?

With highs of 19°C (65°F) and lows of 11°C (52°F) in May, we recommend: Warm evening layer, Comfortable walking shoes. Comfortable walking shoes are essential.

Is May among the best months weather-wise in Millbrae?

May is not the most favourable month weather-wise in Millbrae. Consider visiting during months with milder temperatures or less rainfall for a better experience.

What is the UV index in Millbrae in May?

The average UV index in Millbrae during May is 8 (very high). Strong sun protection is essential — SPF 50+, protective clothing, and avoid prolonged outdoor exposure during peak hours.

How many hours of daylight are there in Millbrae in May?

Millbrae gets approximately 14 hours of daylight per day in May, with around 13 hours of sunshine.

Does it snow in Millbrae in May?

Snow is uncommon in Millbrae during May based on 10-year climate averages.

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