A rough rule of thumb is that for every degree global temperatures increase temperatures on land will go up twice that amount. So with 3.5°C, which is on the low end of what we're headed for, imagine if peak summer temperatures were 13°F higher than they are now.
It entirely depends on how much CO2 and methane we emit, but these sorts of predictions are by convention pegged to 2100. Most of the emissions pathways, unless we stabilize things soon, keep getting hotter until at least 2200.
