Last year, we had our warmest London Marathon on record with 24C recorded at St James Park - a few days after having one of the warmest April days on record.
It had been gruelling for training as March last year had been scuppered by Beast From The East with exceptional snow falls and wind chill, while merely days later we were fast forwarded to early summer and almost leapfrogged spring.
This year, a week later due to Easter last weekend, it's nowhere near as windy and chilly as today.
It's likely to be cloudy with a chance of a few blustery (and fast-paced) showers moving through the capital before it brightens up during the afternoon.
It'll feel cool, more so in the north-west breeze, but better in any spring sunshine - perfect running conditions but spectators might want to be to be prepared with a jumper and brolly.
For the elite runners a cool feeling 12C to start and nearer 16-17C for the masses by the afternoon - much lower than temperatures over last Easter weekend.