It's not in the 100s like Redding and further south but it's still pretty warm here

Mt. Shasta is getting warmer but not necessarily deadly like Redding and from there south in higher temperatures. Here today it is supposed to be 83 which is quite nice up here at 3500 feet in elevation in the mountains. However, tomorrow it goes up to 92 and Monday it goes up to 98 where you have to start being a little more careful of the heat. But, if you have free time you can also drive up a few thousand feet more onto the mountain and it is 10 to 20 degrees cooler usually almost any time of year than here in town. I have been on top of the mountain at around 14, 161 feet or so and even if it were over 100 degrees here on top it was between 30 and 60 degrees even then in August at least during mid day. Also, when you are on top weather changes very quickly from fog and clouds to 100 mile an hour winds so you have to always be on guard for hypothermia, flying ice (if it tries to rain or snow) rock slides, etc.

So, you have to be very very aware of your physical body, what is happening to it and what is going on around you all the time to even survive and ascent onto a mountain this big. All conditions are not at all like at 3500 feet when you embark so being prepared for literally anything is really important.

Though people climb the mountain in all months of the year I would say in some ways it is always equally dangerous because if you aren't worried about freezing to death in the winter you are worried about rockfall caused by climbers above you on the 35% to 45% grades where one little pebble the size of your littlest fingernail dislodges bigger and bigger rocks until one fist size you have to notice to be able to dodge it to survive. I have had to dodge rocks coming down at me at over 60 mph myself. So, being the first up with no one climbing above you is sometimes very important. Also, how careful climbers are above you as they walk is important too to your staying alive. So, freezing to death climbing in the winter times  or being overcome by an avalanche is balanced by being killed by rocks dislodged by climbers above you in spring and summer or dying from altitude sickness when it suddenly comes on you and you become somewhat immobile from throwing up all the time.

So, being really aware of your internal needs as a body in staying alive both externally and internally is what keeps climbers alive climbing mountains. Otherwise you are just another mountain climbing casualty and statistic.

The better you understand yourself, the weather and whatever mountain you are climbing the more likely you will survive it and have great stories to tell your grandchildren one day.