2-2 Features of Monthly Temperature
From late July to late August (Summer), the temperature is the highest of the year.
These days, the high temperature goes up to 37 or 38 degrees celsius. (≈100°F)
You could get a heat stroke without any prevention measure because of the extreme heat.
Between mid December and early March (Winter), the temperature is low.
Especially, late January to early February, the temperature is the lowest of the year.
It has been said since many years ago that Kyoto city is in basin and famous for being chilling to the bone in winter.
But, these days, there are variations in the lowest temperature (-1°C to 4°C, ≈30 to 39°F), and in the highest temperature (5°C to 12°C, ≈41 to 54 °F) during a winter day. So, actually, there are days when it is not so much cold in the daytime of winter season. It depends on the day or the year. (For this year, on some winter days of 2021, it is really cold in the early morning for me.)
In terms of temperature, mid March to early June (Spring), and mid September to early December (Autumn) are most comfortable climate for sightseeing in Kyoto.
If you are OK with cold weather, winter (mid December to early March) is better for sightseeing rather than extreme hot summer.