Still... I'm a Chicago girl, and I keenly remember the feeling that accompanies the bone chilling cold and perpetual grey of a real winter.
It's possible to combat those wintry (or other) blahs with a few yoga poses. Regardless of your geographical location, boost your mood, build some heat, and energize your body with these poses:
When you feel depressed, anxious, or cold your body tends to cave inwards and your shoulders may tense and hunch over. Counter this repressive stance with a heart-opening pose like Bujanghasana (Cobra pose). Imagine reaching your chest forward but don't push or force it. Keep your head nice and supported, and let your shoulders move down and back as your shoulder blades gently draw toward one another. Other effective heart openers include: Supported Corpse pose, Upward Facing Bow (some recognize it as "Wheel"), and Camel.
If you do brave cold climate winters, and want to shake off the chill, try poses that help generate heat in the body. Vasisthasana (Side Plank) is a challenging pose that engages almost all of your your muscles - arms, legs, and core. Keep your hips lifted and in line with your body, from crown of the head to soles of the feet, and imagine your arms are forming a straight line from the wrist of the supporting arm through the fingertips of the lifted arm. Breathe deeply in this pose for 5-10 breaths to feel a noticeable temperature increase. Other poses to generate heat include: Sun Salutation, Bow pose, and Forearm Plank.
Whole Body Energizers
Once you've warmed up, energize your whole body and uplift your moods with poses like Virabhadasana II (Warrior 2.) To get the most benefit, alignment is key. Most practitioners should align the heel of the front foot with the arch of the back foot, to allow the hips and heart to rotate toward the side wall (depending on where you are practicing); keep your front knee directly above your heel, and work toward a 90 degree knee bend. Imagine a long spine with your shoulders aligned directly over your hips. For more strength and energy also try Virabhadrasana I (Warrior 1), Goddess Pose, Dancer pose, or Chair pose.
**If you're feeling adventurous, try adding some dynamic arm movement to your stable Warrior 1, 2, or Goddess foundation like the Universal Yoga Dance of Shiva