During the colder dreary months of winter, you may be inclined to think you should escape to sunny beaches in Florida or Hawaii or Mexico for your vacation. But, I would argue that this is the time to head to California, particularly Monterey Bay. Besides the famous Monterey Bay Aquarium, these months are also the best time for viewing the Monarch Butterflies in Monterey Bay. November to February is the monarch butterfly migration season as they migrate from places that freeze and rest in coastal groves. It’s a very unique experience along Central Coast California as they migrate between Canada to Mexico.
Pacific Grove is one of the locations that have the perfect conditions for the monarch butterflies to rest on their migration path: you can see other locations here along Highway 1 between the Bay Area and Los Angeles. These groves offer the balance of not too cold, but also not too hot, protection from wind and moisture from fog. Of the locations, the Pacific Grove one stands out to me as a do-able day trip from the Bay Area (1.5 hours from San Jose for instance), and has the bonus of the Monterey Bay Aquarium also nearby, or visit on your way to Paso Robles and visit Sensorio in the evening and/or stop in wine country, etc. so you can easily plan multiple diverse activities on your itinerary.
You can track the latest monarch butterfly counts at the Pacific Grove website or on their Instagram. the numbers were depressingly low the past few years, dropping from the millions into the thousands. The numbers are starting to rebound as people (including you!) can follow the call to action to help preserve them – they still desperately need your help. Until they recover, you may need to temper your expectations of how many butterflies you may see – thus checking the counts before your trip. During my trip, the count was around 15-16,000 during the first weekend of December.
The Pacific Grove Monarch Sanctuary is only 2 miles away from Monterey Bay and has free admission, and free parking. Note that pets are not permitted since the butterflies may be everywhere and anywhere including on the ground, and you and your pets don’t want to disturb these delicate creatures as they rest – and the fine is $1000 for touching a butterfly.
During the early winter, such as during my visit, because of the generally colder temperatures you are more likely to see them clustering in the trees. Definitely bring your binoculars – at first it may be difficult to spot them because they almost look like leaves as they are camouflaged in clusters with their closed wings. If you visit between the times of 12-3pm, there will be a free docent there who can provide more detailed stories then the handful of signs in the sanctuary and may have a tripod with set binoculars to take a look. 
As winter starts to thaw into spring, or the weather warms up later in the day, you may be fortunate enough to see them alight into the air. Here, all the “brown leaves” you see are butterflies! The clusters can be up to 1000 butterflies,. Any photos you take will likely depend on how good your zoom is on your camera and have patience. Also look for where there are flowers as you may see one or two scattered resting on a flower, or on the ground.
Fun fact as you are looking at them – you can distinguish between male and female butterflies by looking at their wings carefully. Female butterflies tend to have thicker veins and be slightly darker in color, while males have two black dots on their hind wings and fork-like claspers at the end of the abdomen. For me the easiest to see were the dots – there’s a female to the left and male to the right below.
Of course if you have not yet, definitely visit the world famous Monterey Bay Aquarium if you have never been, and include some time to walk around the Cannery Row, an area of restaurants and shops where the aquarium is situated – touristy but you can find a donut bar, ice cream options, crepes, and other food options if you don’t want to dine at the aquarium cafe. For something unique check out Troya Turkish Delight & Baklava for Turkish tea and sweets like a huge variety of Turkish delights. There’s a cute downtown area of shops and restaurants also on Lighthouse Avenue on your way between the aquarium and Pacific Grove Monarch Sanctuary, around where the Pacific Grove Museum of Natural History is located. If you have more time, consider a drive along 17-Mile Drive to visit the Lone Cypress and enjoy the views of wind carved trees along the coastline here.
If you are coming from or to the Bay Area before or after your trip, I would like to suggest two other interesting stops for your consideration. Along the drive south, you will see the city of Gilroy, Garlic Capital of the World. There are various restaurants and shops and even a small family-friendly amusement park of Gilroy Gardens, most noticeably pulloffs from the highway for the Garlic Shoppe and Garlic World. Having visited both, Garlic World is the larger shop with nicer restrooms and a seating area to enjoy garlic ice cream and you can check out the world’s largest garlic braid, though Garlic Shoppe does have the plus of some farm animals on their property if you don’t mind standing to dine al fresco looking at the animals. 
Additionally, you can stop at the “World’s Largest Artichoke” which is conveniently located next to the Giant Artichoke Restaurant where you can find artichokes in all sorts of forms to try, varying from in breakfast omelets and benedicts, to burgers and pasta or an enchilada, or the gamut of appetizer options from deep fried, steamed, roasted, embedded in dips or bread or cupcakes! If you don’t have time to dine in at the restaurant, the market next door does have a stand to grab made to order fried artichokes. As you drive past on the highway, you can see the artichoke plants in the fields.
I hope you have a chance to see monarch butterflies and support them by limiting use of pesticides and even plant host plants like milkweed and nectar plants and support the monarch corridors. In general, I am also advocating to support as many local businesses as you can in the off-season of winter – they need your patronage to stay in business exactly when the crowds are not there and the weather isn’t as nice. The plus is that there are less lines, and a more relaxed feel to your vacation.
Thank you.