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The temperatures in Union in September are comfortable with low of 16°C and and high up to 25°C.
You can expect about 3 to 8 days of rain in Union during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Union in September 2025.
If you’re planning to visit Union in the near future, we highly recommend that you review the 14 day weather forecast for Union before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 3° / -4° | 7 | 21 | 3 | 88 mm | Awful | Union in January |
| February | 5° / -3° | 7 | 17 | 4 | 95 mm | Awful | Union in February |
| March | 9° / 1° | 8 | 21 | 2 | 119 mm | Awful | Union in March |
| April | 16° / 6° | 7 | 23 | 0 | 114 mm | Ok | Union in April |
| May | 21° / 12° | 9 | 22 | 0 | 113 mm | Ok | Union in May |
| June | 26° / 17° | 9 | 21 | 0 | 125 mm | Good | Union in June |
| July | 30° / 21° | 11 | 21 | 0 | 132 mm | Ok | Union in July |
| August | 29° / 20° | 9 | 22 | 0 | 128 mm | Ok | Union in August |
| September | 25° / 16° | 7 | 23 | 0 | 107 mm | Good | Union in September |
| October | 18° / 11° | 7 | 24 | 0 | 136 mm | Ok | Union in October |
| November | 12° / 4° | 6 | 24 | 0 | 87 mm | Ok | Union in November |
| December | 6° / 0° | 8 | 22 | 2 | 129 mm | Awful | Union in December |
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