Friday, March 3, 2017

Wettest and Driest Months / Seasons

What are the wettest and driest months of the year? Using published normal values, we can answer that question. These maps were generated using the 1981-2010 NCEI climate normals for monthly precipitation within the U.S. In Canada and Mexico (and the rest of the globe [not shown]), the GHCN v.2 monthly precipitation was used.

To standardize the months due to differences in the number of days, I used an average daily precipitation value. In a few instances, this will cause discrepancies. For example, if February averages 3.00" of precipitation and March averages 3.10", I show February as having more precipitation – since their per-day value is higher.

On the mapping side of things, how do you interpolate a month between two stations where one is wettest in December and the other is wettest in January. If you average the month numbers (12 and 1), you end up with June being the wettest month! Obviously this is not correct. I used trigonometric functions to compute these polar-coordinate averages. Still, there are boundary issues when nearby stations have vastly different wettest or driest months.


There are four sets of maps. 

1) Wettest / Driest month of the year (color shaded)
2) Wettest / Driest month of the year (station dots)
3) Wettest / Driest season of the year (color shaded)
4) Wettest / Driest season of the year (station dots)

Note: Seasons are based on calendar months (e.g., winter = December through February).

Wettest / Driest month of the year (color shaded)

Figure 1. Wettest month of the year based on climate normals (color shaded).

Figure 2. Driest month of the year based on climate normals (color shaded).

Wettest / Driest month of the year (station dots)


Figure 3. Wettest month of the year based on climate normals (station dots).


Figure 4. Driest month of the year based on climate normals (station dots).


Wettest / Driest season of the year (color shaded)

Figure 5. Wettest season of the year based on climate normals (color shaded).

Figure 6. Driest season of the year based on climate normals (color shaded).


Wettest / Driest season of the year (station dots)


Figure 7. Wettest season of the year based on climate normals (station dots).

Figure 8. Driest season of the year based on climate normals (station dots).


5 comments:

  1. Interesting breakdown of the wettest and driest months. It’s super helpful, especially for planning trips where weather matters. For example, if someone’s applying for an Umrah Visa, knowing whether it’ll be scorching dry or pouring rain makes travel smoother. Timing really changes the whole experience.

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  2. Really interesting breakdown of the wettest and driest months. As someone who loves planning trips, knowing these details makes a huge difference. A travel agent agency could use this info to guide clients toward the best times for outdoor activities or sightseeing without weather surprises.

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  3. Interesting breakdown of the wettest and driest months. I noticed during my recent nathia gali tour that July really lived up to being the wettest month, with heavy rains almost every afternoon. On the other hand, October felt perfectly dry, making hikes more enjoyable.

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  4. Interesting breakdown of the wettest and driest months! Iptv Canada makes it easy to follow weather updates in real time, which is handy for planning trips or outdoor activities. Knowing seasonal rainfall trends helps avoid surprises, and Iptv Canada keeps everything accessible and accurate for viewers.

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  5. Interesting breakdown of the wettest and driest months! It’s surprising how rainfall shifts seasonally, affecting daily life. For those staying indoors during the wettest months, having entertainment options like Best IPTV Canada can make a big difference. Driest seasons feel more freeing, yet Best IPTV Canada keeps routines fun regardless.

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