Elk River WMA
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Elk River WMA clear sky chart from 2005-11-06 to 2024-02-10.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	18% 10% 4 6% 6% 3 5% 5% 5% 7% 31%	78161
	Night	18% 11% 4 7% 5% 3 4 4 5% 6% 32%	80811
Transparency	Day	53% 6% 10% 19% 11% 2	77882
	Night	53% 5% 10% 18% 12% 2	80609
Seeing	Day	27% 13% 24% 21% 12% 4	13881
	Night	26% 11% 22% 27% 13% 2	24294

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	19% 21% 9% 8% 7% 2 3 3 3 5% 19%	2836
	11th to 20th	Day	19% 22% 10% 12% 7% 3 3 2 2 3 17%	2840
	21st to end	Day	22% 20% 7% 9% 7% 3 3 3 3 5% 20%	3124
February	1st to 10th	Day	20% 14% 6% 10% 6% 3 4 3 4 5% 25%	1701
	11th to 20th	Day	22% 16% 5% 9% 5% 4 4 3 4 4 24%	1619
	21st to end	Day	25% 15% 4 8% 5% 2 3 4 4 4 26%	1502
March	1st to 10th	Day	18% 13% 5% 5% 4 2 4 4 5% 5% 35%	1980
	11th to 20th	Day	22% 11% 5% 7% 5% 3 4 4 5% 6% 29%	1980
	21st to end	Day	22% 12% 3 7% 5% 3 4 4 5% 6% 29%	2178
April	1st to 10th	Day	17% 12% 4 6% 5% 3 4 4 5% 7% 33%	2033
	11th to 20th	Day	18% 8% 4 5% 4 3 4 4 5% 7% 39%	2157
	21st to end	Day	23% 8% 3 5% 5% 3 5% 5% 6% 6% 31%	2340
May	1st to 10th	Day	22% 7% 3 6% 7% 3 5% 4 5% 7% 29%	2340
	11th to 20th	Day	23% 7% 3 6% 6% 3 5% 5% 5% 8% 30%	2301
	21st to end	Day	13% 5% 3 6% 7% 5% 5% 6% 7% 9% 34%	2531
June	1st to 10th	Day	14% 5% 3 6% 6% 3 5% 6% 6% 8% 37%	2340
	11th to 20th	Day	13% 6% 3 7% 6% 4 6% 6% 7% 9% 33%	2340
	21st to end	Day	13% 5% 3 6% 6% 3 5% 6% 7% 10% 35%	2340
July	1st to 10th	Day	13% 6% 2 6% 7% 4 6% 7% 6% 10% 35%	2340
	11th to 20th	Day	13% 6% 2 6% 6% 3 6% 7% 6% 8% 37%	2340
	21st to end	Day	16% 6% 3 5% 6% 5% 7% 6% 7% 8% 33%	2547
August	1st to 10th	Day	12% 6% 3 6% 6% 4 6% 7% 8% 9% 30%	2327
	11th to 20th	Day	15% 6% 3 6% 7% 4 6% 6% 7% 8% 31%	2303
	21st to end	Day	12% 6% 2 6% 5% 4 6% 6% 7% 9% 37%	2453
September	1st to 10th	Day	14% 6% 2 4 5% 3 5% 5% 5% 7% 43%	2100
	11th to 20th	Day	14% 5% 2 5% 4 4 5% 6% 5% 8% 43%	1980
	21st to end	Day	19% 7% 3 5% 5% 3 3 5% 5% 7% 38%	1980
October	1st to 10th	Day	18% 5% 2 5% 5% 2 3 3 5% 8% 43%	1832
	11th to 20th	Day	20% 9% 2 5% 5% 3 3 4 5% 5% 41%	1800
	21st to end	Day	23% 9% 2 5% 4 2 3 5% 4 7% 37%	1980
November	1st to 10th	Day	14% 7% 3 5% 5% 3 3 4 4 5% 46%	1806
	11th to 20th	Day	17% 11% 3 5% 4 2 6% 4 5% 7% 35%	1710
	21st to end	Day	18% 15% 4 5% 4 3 5% 4 4 6% 32%	1592
December	1st to 10th	Day	27% 14% 6% 8% 5% 2 4 4 4 4 21%	1520
	11th to 20th	Day	22% 17% 5% 9% 5% 2 2 3 3 6% 26%	1945
	21st to end	Day	21% 18% 5% 7% 6% 3 5% 6% 5% 6% 17%	3124
January	1st to 10th	Night	19% 26% 7% 8% 5% 3 3 3 3 4 19%	4109
	11th to 20th	Night	21% 17% 6% 12% 8% 3 3 3 3 4 20%	4120
	21st to end	Night	28% 16% 6% 8% 8% 2 3 3 2 4 21%	4532
February	1st to 10th	Night	20% 14% 6% 8% 6% 3 4 4 4 5% 26%	2464
	11th to 20th	Night	22% 16% 4 9% 7% 3 4 4 4 4 24%	2223
	21st to end	Night	26% 14% 5% 7% 5% 2 3 4 4 6% 24%	1753
March	1st to 10th	Night	19% 13% 4 6% 5% 3 4 4 4 5% 34%	1980
	11th to 20th	Night	24% 11% 4 6% 5% 2 3 3 4 7% 31%	1980
	21st to end	Night	23% 11% 4 6% 3 3 4 5% 4 5% 31%	2178
April	1st to 10th	Night	19% 11% 4 6% 4 2 4 4 4 6% 35%	1926
	11th to 20th	Night	15% 7% 2 5% 5% 3 5% 5% 7% 8% 38%	1767
	21st to end	Night	18% 8% 3 7% 6% 4 4 5% 5% 6% 36%	1620
May	1st to 10th	Night	22% 7% 3 6% 5% 3 5% 4 5% 6% 33%	1620
	11th to 20th	Night	19% 9% 4 7% 5% 3 4 6% 6% 9% 30%	1592
	21st to end	Night	13% 5% 2 5% 6% 3 5% 5% 6% 9% 40%	1744
June	1st to 10th	Night	12% 6% 3 4 5% 3 6% 5% 7% 8% 41%	1620
	11th to 20th	Night	10% 6% 3 6% 6% 4 6% 6% 7% 9% 38%	1620
	21st to end	Night	12% 5% 3 4 4 3 4 5% 8% 10% 42%	1620
July	1st to 10th	Night	11% 6% 3 7% 5% 4 5% 5% 6% 10% 37%	1620
	11th to 20th	Night	10% 5% 2 6% 5% 3 5% 4 9% 10% 40%	1620
	21st to end	Night	11% 5% 3 5% 5% 3 6% 6% 8% 10% 37%	1771
August	1st to 10th	Night	10% 7% 3 6% 6% 4 5% 7% 7% 10% 36%	1611
	11th to 20th	Night	14% 5% 3 6% 5% 4 4 5% 7% 9% 40%	1598
	21st to end	Night	11% 5% 2 5% 5% 3 5% 5% 6% 9% 45%	1885
September	1st to 10th	Night	13% 6% 2 4 6% 3 5% 4 6% 7% 43%	1856
	11th to 20th	Night	14% 5% 3 3 3 3 4 4 5% 6% 51%	1980
	21st to end	Night	16% 6% 2 4 4 3 5% 4 6% 7% 42%	1980
October	1st to 10th	Night	16% 4 2 5% 5% 2 4 5% 4 8% 45%	2128
	11th to 20th	Night	18% 7% 2 5% 4 4 4 4 5% 7% 41%	2160
	21st to end	Night	24% 7% 2 5% 4 2 4 4 3 5% 39%	2376
November	1st to 10th	Night	15% 8% 3 5% 4 2 4 4 4 5% 45%	2268
	11th to 20th	Night	20% 13% 4 5% 4 3 3 4 5% 6% 34%	2470
	21st to end	Night	19% 11% 5% 7% 5% 3 5% 4 4 5% 31%	2584
December	1st to 10th	Night	24% 18% 6% 8% 5% 3 4 3 3 5% 21%	2660
	11th to 20th	Night	21% 17% 7% 8% 4 3 3 3 4 5% 24%	3244
	21st to end	Night	21% 19% 5% 8% 7% 3 4 4 4 4 21%	4532

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	70% 4 7% 12% 7%	2837
	11th to 20th	Day	76% 2 5% 11% 5%	2840
	21st to end	Day	70% 3 6% 16% 5% 1	3124
February	1st to 10th	Day	64% 4 8% 16% 7%	1701
	11th to 20th	Day	65% 4 7% 15% 7% 1	1628
	21st to end	Day	63% 4 7% 15% 10% 1	1502
March	1st to 10th	Day	51% 4 10% 22% 11% 1	1980
	11th to 20th	Day	56% 6% 8% 17% 11% 2	1980
	21st to end	Day	58% 5% 7% 18% 10% 2	2178
April	1st to 10th	Day	51% 5% 10% 17% 14% 3	2033
	11th to 20th	Day	46% 5% 10% 18% 17% 4	2157
	21st to end	Day	52% 6% 11% 18% 11% 2	2340
May	1st to 10th	Day	55% 7% 9% 18% 9% 2	2340
	11th to 20th	Day	54% 7% 12% 17% 9% 2	2305
	21st to end	Day	45% 9% 15% 21% 9% 1	2531
June	1st to 10th	Day	43% 8% 13% 21% 14% 1	2340
	11th to 20th	Day	46% 9% 12% 20% 12% 1	2340
	21st to end	Day	44% 8% 13% 23% 11% 1	2340
July	1st to 10th	Day	45% 9% 13% 19% 12% 3	2275
	11th to 20th	Day	42% 9% 13% 20% 14% 2	2271
	21st to end	Day	46% 9% 11% 21% 12% 2	2405
August	1st to 10th	Day	46% 9% 15% 21% 8% 1	2314
	11th to 20th	Day	48% 9% 12% 22% 9% 1	2303
	21st to end	Day	41% 8% 16% 21% 12% 2	2453
September	1st to 10th	Day	40% 7% 11% 20% 18% 4	2100
	11th to 20th	Day	38% 7% 11% 24% 17% 2	1980
	21st to end	Day	45% 5% 9% 22% 16% 1	1980
October	1st to 10th	Day	41% 5% 11% 23% 17% 3	1832
	11th to 20th	Day	47% 5% 8% 23% 17%	1800
	21st to end	Day	49% 4 9% 20% 14% 2	1980
November	1st to 10th	Day	42% 4 7% 24% 18% 4	1806
	11th to 20th	Day	49% 5% 8% 18% 16% 4	1710
	21st to end	Day	55% 5% 9% 18% 13% 1	1592
December	1st to 10th	Day	67% 4 6% 16% 5% 1	1520
	11th to 20th	Day	62% 3 8% 15% 11% 1	1941
	21st to end	Day	66% 6% 10% 14% 5%	3124
January	1st to 10th	Night	72% 3 7% 12% 6% 1	4109
	11th to 20th	Night	71% 4 7% 15% 4	4120
	21st to end	Night	71% 4 5% 13% 6% 1	4532
February	1st to 10th	Night	62% 5% 9% 16% 9%	2464
	11th to 20th	Night	66% 3 7% 14% 9% 1	2225
	21st to end	Night	63% 4 7% 14% 8% 3	1753
March	1st to 10th	Night	55% 4 8% 21% 12% 2	1980
	11th to 20th	Night	56% 4 10% 19% 11% 1	1980
	21st to end	Night	56% 6% 7% 16% 13% 3	2178
April	1st to 10th	Night	52% 4 8% 19% 14% 2	1926
	11th to 20th	Night	43% 6% 13% 17% 16% 5%	1767
	21st to end	Night	49% 5% 12% 18% 13% 2	1620
May	1st to 10th	Night	52% 7% 10% 17% 12% 2	1620
	11th to 20th	Night	51% 9% 12% 17% 10% 2	1593
	21st to end	Night	40% 9% 16% 25% 9% 1	1745
June	1st to 10th	Night	40% 8% 13% 24% 14% 1	1620
	11th to 20th	Night	42% 11% 14% 19% 13% 2	1620
	21st to end	Night	36% 9% 15% 25% 14% 1	1620
July	1st to 10th	Night	42% 10% 13% 19% 14% 2	1575
	11th to 20th	Night	36% 9% 16% 22% 14% 3	1566
	21st to end	Night	39% 9% 15% 23% 14%	1672
August	1st to 10th	Night	42% 9% 16% 22% 10% 1	1600
	11th to 20th	Night	40% 8% 15% 24% 12% 1	1598
	21st to end	Night	35% 7% 15% 26% 14% 3	1885
September	1st to 10th	Night	39% 7% 14% 20% 17% 4	1856
	11th to 20th	Night	35% 5% 12% 24% 22% 3	1980
	21st to end	Night	41% 6% 11% 23% 18% 1	1980
October	1st to 10th	Night	38% 6% 11% 24% 18% 3	2128
	11th to 20th	Night	43% 5% 8% 23% 19% 2	2160
	21st to end	Night	49% 4 6% 21% 17% 3	2376
November	1st to 10th	Night	42% 5% 10% 18% 20% 7%	2268
	11th to 20th	Night	52% 4 8% 16% 17% 4	2470
	21st to end	Night	56% 5% 7% 17% 14% 2	2584
December	1st to 10th	Night	67% 4 7% 16% 5% 1	2660
	11th to 20th	Night	65% 4 8% 14% 9% 1	3247
	21st to end	Night	67% 4 7% 14% 7%	4532

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	34% 29% 21% 11% 4	270
	11th to 20th	Day	42% 26% 24% 7%	270
	21st to end	Day	41% 24% 24% 9% 2	297
February	1st to 10th	Day	39% 22% 28% 9% 2	267
	11th to 20th	Day	50% 23% 21% 7%	240
	21st to end	Day	46% 18% 28% 8%	220
March	1st to 10th	Day	36% 18% 29% 14% 3	420
	11th to 20th	Day	37% 23% 21% 13% 5% 1	420
	21st to end	Day	37% 16% 27% 15% 4 1	462
April	1st to 10th	Day	33% 20% 23% 19% 4	420
	11th to 20th	Day	29% 13% 29% 16% 10% 3	412
	21st to end	Day	35% 17% 25% 14% 6% 2	420
May	1st to 10th	Day	35% 14% 27% 12% 9% 3	423
	11th to 20th	Day	29% 11% 27% 19% 10% 3	447
	21st to end	Day	18% 8% 23% 25% 20% 7%	485
June	1st to 10th	Day	17% 10% 24% 26% 16% 7%	450
	11th to 20th	Day	20% 8% 26% 22% 17% 6%	450
	21st to end	Day	15% 10% 28% 27% 15% 5%	450
July	1st to 10th	Day	16% 7% 17% 26% 22% 12%	445
	11th to 20th	Day	13% 4 20% 34% 19% 10%	444
	21st to end	Day	19% 6% 21% 24% 20% 10%	488
August	1st to 10th	Day	14% 6% 20% 31% 19% 10%	446
	11th to 20th	Day	18% 4 17% 32% 20% 10%	439
	21st to end	Day	15% 5% 19% 30% 21% 10%	495
September	1st to 10th	Day	16% 7% 16% 28% 24% 9%	450
	11th to 20th	Day	14% 5% 14% 33% 24% 10%	450
	21st to end	Day	24% 7% 25% 24% 16% 3	450
October	1st to 10th	Day	21% 8% 24% 23% 17% 6%	450
	11th to 20th	Day	25% 12% 25% 24% 12% 2	450
	21st to end	Day	29% 16% 24% 22% 8% 1	495
November	1st to 10th	Day	22% 13% 27% 26% 10% 2	404
	11th to 20th	Day	36% 15% 25% 16% 7% 1	270
	21st to end	Day	31% 17% 34% 15% 2 1	214
December	1st to 10th	Day	39% 20% 24% 13% 3 1	180
	11th to 20th	Day	38% 15% 26% 15% 6%	191
	21st to end	Day	39% 18% 27% 12% 4	297
January	1st to 10th	Night	37% 19% 26% 14% 4	760
	11th to 20th	Night	38% 18% 24% 19% 2	760
	21st to end	Night	34% 19% 27% 18% 2	836
February	1st to 10th	Night	31% 18% 26% 22% 3	759
	11th to 20th	Night	36% 21% 27% 14% 1	703
	21st to end	Night	38% 18% 28% 15% 1	592
March	1st to 10th	Night	32% 16% 26% 23% 3	720
	11th to 20th	Night	34% 17% 25% 17% 6% 1	720
	21st to end	Night	33% 13% 28% 20% 5% 1	792
April	1st to 10th	Night	30% 15% 28% 22% 4	720
	11th to 20th	Night	20% 13% 30% 25% 11% 1	703
	21st to end	Night	24% 10% 31% 25% 9%	540
May	1st to 10th	Night	26% 10% 27% 26% 10% 1	540
	11th to 20th	Night	25% 7% 25% 30% 11% 1	531
	21st to end	Night	15% 3 22% 34% 22% 5%	584
June	1st to 10th	Night	14% 4 19% 38% 23% 3	540
	11th to 20th	Night	14% 4 17% 39% 24% 3	540
	21st to end	Night	16% 3 18% 41% 19% 2	540
July	1st to 10th	Night	15% 5% 10% 39% 26% 5%	525
	11th to 20th	Night	13% 4 13% 36% 28% 5%	522
	21st to end	Night	15% 3 10% 37% 30% 5%	591
August	1st to 10th	Night	14% 3 11% 38% 31% 3	537
	11th to 20th	Night	17% 4 9% 37% 29% 5%	534
	21st to end	Night	13% 3 10% 37% 30% 6%	697
September	1st to 10th	Night	17% 3 15% 32% 29% 4	720
	11th to 20th	Night	15% 4 14% 34% 29% 5%	720
	21st to end	Night	19% 6% 21% 30% 23% 2	720
October	1st to 10th	Night	19% 6% 18% 32% 21% 3	720
	11th to 20th	Night	25% 9% 23% 28% 13% 2	720
	21st to end	Night	31% 9% 21% 28% 9% 1	792
November	1st to 10th	Night	21% 9% 23% 31% 14% 1	740
	11th to 20th	Night	31% 14% 24% 22% 8% 1	760
	21st to end	Night	29% 14% 26% 25% 6% 1	760
December	1st to 10th	Night	38% 16% 22% 20% 4	760
	11th to 20th	Night	31% 20% 23% 23% 3	760
	21st to end	Night	33% 15% 27% 22% 2	836

Page generated at 2024-02-07 06:11:59. Version ac07

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