I start feeling it at the end of June, which is when I become progressively more bummed out. The first week of July it gets worse, with sadness peaking on July 5 or 6 every year. It's an especially strange time to be down in the dumps, since it seems like everyone is celebrating summer and the Fourth of July holiday.

There's a reason for my feelings: The first part of July is both the birthday and death-day for my grandmother, who raised me. Born on July 9, 1918, she died on Independence Day 80 years later. The 18 years we had together were not nearly enough.

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I'm far from the only one who has sadness or other emotional reaction to a certain time of year. Dr. John Sharp, a psychiatrist in practice for more than 20 years, says he has seen many patients who have a specific and deep emotional reaction tied to the calendar.

Sharp's book, "The Emotional Calendar," tackles the idea that if you know how your mood is affected by personal, cultural and environmental changes throughout the year, the better you will be able to deal with them.

That's what knowing your emotional calendar is all about. For example, although my grandmother has been gone for 17 years, I'm not any less sad during that week in July. So now, I just don't plan much then. It's a good time to just keep my head down and focus on work because I don't have any expectations about feeling great. I allow myself room to take long walks, or to cry, or to just spend time thinking about my grandma. I'm sad, and that's OK.

As Sharp writes about spring: "Counter-intuitively, some people feel really overwhelmed with all the increased energy and life force that comes with this season. As a striking example of this, suicides peak in April. Beware. Seek support and counseling if you feel out of sync with the season's positive offering."

For other people, events from their past might trigger specific feelings. It could be that certain holidays have a special significance or that the New Year scares them because it reminds them of time passing.

While the start of the school year feels like an exciting fresh start for some, others might experience quite a bit of anxiety about it. Dr. Sharp writes about how he sees late winter as a time to get away, based on years of Spring break vacations to warmer climes.

Of course, there are physical seasonal changes too. The most intense is seasonal affective disorder (SAD), during which sufferers are negatively affected by waning light levels. But cooler (or warmer) temperatures, snow — or a lack of it — also can change moods in less dramatic ways.

What's your emotional calendar like? Where does it align with those around you and where might it differ? Spending a few minutes at the start of each season thinking ahead to what's coming and what you really need could help you avoid over-extending yourself, or being unprepared for feelings, positive or negative.

I know I like quiet and solitude around Christmas and New Year's and I no longer feel guilty for craving this time to myself, even though it's not what's "expected" that time of year. At the end of January and for most of February, I get a burst of energy. I'm guessing it's tied to the new year that starts after my birthday then. I get sad in July, and excited in September, when the new school year starts, even though I don't have kids, don't teach, and am no longer a student. I can harness that energetic time to get a lot done or start new projects.

How about you?

Starre Vartan ( @ecochickie ) covers conscious consumption, health and science as she travels the world exploring new cultures and ideas.