Booking with Air Transat 41 days in advance of your planned departure date is, on average, the best time to get cheap flights from Calgary to London. The general trend is that the closer you book to the departure date, the more expensive your flight will be.
In terms of precipitation, rainfall in London ranges from 40.0 - 70.0 mm per month. January is typically the wettest month, when rainfall can reach 70.0 mm. July is typically the driest time to visit London when rainfall is around 40.0 mm.
If weather is an important factor for your trip to London, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 17.0 C. Travellers hoping to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 4.0 C).
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