Hi Varun,
I grew up in Michigan before moving out to Baltimore, so I'm a bit skewed when it comes to the weather here, but I'll give my least biased response. The weather is fairly mild during the winter, but still bites at night. Right now, we are in the mid 50s in the day and mid 30s at night, and it's pretty immediate once the sun goes down, the temp rapidly drops. We got like 2 inches of snow total last winter, but the temps in Jan and Feb were a little on the nippy side (like 30s in the day not counting the wind). Spring and Fall are pleasant but humid, the summer is scorching and humid and nasty. Like 90s everyday with the feels like above 100. I hate the heat though so there's my bias showing.
As for tips, Charles Village is a nice spot to live, all the JHU undergrads can be found there. Fells Point and Canton are nice (where I live) and have some great eating spots. If you're bringing a car, expect to be frustrated with parking and please please PLEASE know how to parallel park. Always be vigilant walking around, groups are better to be in, especially at night. Expect between $600 and $900 for an apartment not counting utilities, and most meals out to eat are $15- 25, though you can easily go higher or lower depending on specials and where you are.