I very much remember it, as my wife and I were both out of work at the time thanks to Covid, and we have a south-facing balcony - so April 2021 in the daytime was fantastic, with the sun low enough in the sky to fully illuminate the covered balcony.
However, we made the mistake of heading for our first post-lockdown pint one afternoon, and sat outside a hastily rearranged BrewDog, basking in the sun in t-shirts and jeans.
But the second the sun even went behind a building at ~6pm we had to run back home, so sudden was the temperature drop.
I also remember snow/graupel showers in London