Hi…..
In any kind of weather you want.

Bill
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My dad likes to tell this funny story about the 1950's. He had a friend with a Vespa scooter. They're just like scooters today, with a full faired windshield. He got on the back, holding an umbrella, while his friend was driving. He just put the front edge of the umbrella behind the top of the windshield, and they were dry!

You don't want to do that, of course. You'll need to put on a rain suit. You can go anywhere you want in the rain wearing a rain suit.

You have to be careful, though, about the road being slick when it rains. Paint used on the road (the reflective kind) is especially slick in the rain, and you'll have to be careful.
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when i lived in Colorado Ive ridden in snow rain fog and sunshine all on the same day.

i will tell you rain stings like all get out over 40mph. that is the one time i always wear a brain bucket
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Its been said, what can you take? I live in Phoenix, I've ridden in rain storms bad enough that some puddles were axle deep (and I don't own a rain suit), and temperatures up near 120˚ not always fun, but it can be done.
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You will definitely save money on fuel and wear-and-tear on your car. Insuring a scooter is generally fairly inexpensive as well, and the operating costs if you do your own maintenance are inexpensive too. In the 2,400 miles I've put on my Vino 125 I've spent about $80 on fuel and $20 on oil (the transmission oil was expensive, but the bottle will last me another 10,000 miles).

You can often save money by taking the Basic Rider Course from the Motorcycle Safety Foundation. In many states, successfully passing the course will also let you waive a skills test for a Motorcycle License from your DMV, but check with them. Your Ruckus probably will only require you have a standard driver's license, but regardless of that, you face the SAME dangers EVERY motorcyclist faces on the road.

Your riding time is limited only by your assessment of your riding skills and risk.

Most people would not ride any two wheeled vehicle when there is obvious snow or ice on the road. I would also avoid riding when it's near freezing temperatures, or when there's a lot of salt on the road - you're not going to want your scoot to get that gunk on it

Most people will also avoid riding in rain, though I don't mind it as long as it's not a driving rain and the winds are decent. I would also avoid riding if there is lightning in the area.

Many people also do not like riding in the wind. A scooter is a light vehicle and does blow around quite a bit. I've rode my Yamaha Vino 125 in gusts of 30MPH and it's an interesting experience to say the least, however, as you get used to it you will become more comfortable.

It will get cold to ride on the scooter much below 65 degrees - assume you're going 30 miles per hour, that's like having a 30mph wind and associated wind chill on you.

If you're going to do all-weather riding, invest in the following:

A) Good Waterproof all-weather motorcycle jacket or a Rain Jacket to put on top of your normal jacket if it's not waterproof.
B) Suitable Rain Pants
C) A full-face, 3/4, or modular helmet that can accept an anti-fog shield
D) Waterproof gloves for warmer weather
E) Waterproof gloves for cooler weather
F) Waterproof boots.
G) A neck gaiter or balaclava if you're going to ride much below 50 degrees.

When you look for gear, buy the best you can afford, and buy motorcycle-specific gear. I recommend the full-face, 3/4, or modular helmet because any amount of rain at speed will feel like someone is shooting nails at you!
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http://www.msf-usa.org/

In addition to the other fine answers, I will add my bit.
- I avoid heavy stop-and-go traffic with irrate cagers (drivers) like in city-centers during rush hour. It is do-able, just be careful.
- be careful in parking lots, exiting from a stadium, drive-in theatre, etc where people are feeling feisty and obnoxious.
- watch out for ice on the shaded side of curves in the winter.
- loose dogs and cats can be hazards. Deer are a very real danger at night especially.

Buy the book "Proficient Motorcycling" and keep it by the throne.

Take a Motorcycle Safety Foundation course.

I have a Honda Reflex 250cc scooter with ABS brakes, with the front & rear brakes interlocked (like on my old Moto Guzzi). This adds a significant saftey factor once you are IN a dangerous situation. The trick, of course, is learning to recognize and avoid these situations to begin with (thus the book and class recommendation).

I think the Ruckus is a durable, fun and reliable machine that you could get years and years of use from. Just be sensible, be wary, ride for years and save money and have fun.

GeoB
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I just got back from a commute on my motorcycle in pouring rain. It's not too bad if you have a full body rain suit to put on, and wet pavement you can still ride on if you're careful. I'm still trying to figure out how to ride in near freezing weather; I may have to get a snowmobile suit or electric vest. I've also ridden down gravel roads on a sport bike; the Ruckus was actually designed with off roading in mind.

The real danger is ice. It's a common joke in the two wheeled world: "There are two key techniques to riding safely across an ice covered road. Unfortunately, nobody knows what they are."
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Ride in any weather with one exception.
You should have the confidence to do so.

I strongly suggest that you take a motorcycle safety course. The instructors can speak specifically to techniques you should use during rain that will reduce your risks of injury to yourself or others.

Scott