Unión Weather in May
What's the weather like in Unión (San Luis) in May 2026?
The climate in Unión during May can be summarized as mild and dry.
May is in the fall / autumn in Unión and is typically the 4th coldest month of the year. Daytime maximum temperatures average around a cool 20°C (68°F), whilst at night 5°C (42°F) is normal.
| Daytime temperature | 20°C 67.9°F |
|---|---|
| Nightly temperature | 5.3°C 41.5°F |
| Average temperature | 12.6°C 54.7°F |
| Daily sunshine | 6.4 hrs |
| Avg rainfall | 21 mm 0.8 ins |
| Rainy days | 4 days |
| Sea temperature | 15°C 59.1°F |
| Humidity | 71% |
| Windspeed | 7.6kph 5 mph |
On average May is the 4th driest month of the year in Unión with around 21mm 0.8 inches of rain making it a dry time to visit. This rainfall is typically spread over 4 days, although this may vary considerably.
On the flip side this corresponds to an average of 6.4 hours of sunshine per day.
May temperatures in Unión
May rainfall
May hourly sunshine
The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Unión in May 2025.
Other monthly averages
Unión weather stats
| Hottest month: | January | 31.8°C 89.2°F |
|---|---|---|
| Driest month: | June | 10mm 0.4ins |
| Sunniest month: | February | 10.7hrs |
| Coldest month: | July | 16°C 60.8°F |
| Wettest month: | December | 75mm 3ins |
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