To be safe, bring along an umbrella any time of year.
Don't forget to bring a sweater and jacket in winter as it can get rather chilly, with temperatures falling to as low as 8 degrees at night.
Alternatively, when the sun makes an appearance for a day or a week, it can reach 30 degrees.
It's usually quite dry during the summer months, when the temperature can reach the high 30's.
Summer rains can be heavy but brief, and often arrive unexpectedly, whereas February rains can last for weeks.