AUGO Fort Vermillion
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the AUGO Fort Vermillion clear sky chart from 2005-11-06 to 2024-11-02.

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	9% 8% 3 8% 6% 5% 5% 4 7% 8% 36%	102474
	Night	8% 11% 4 10% 6% 5% 5% 4 6% 8% 32%	96541
Transparency	Day	43% 9% 18% 23% 7%	102185
	Night	47% 9% 16% 21% 7%	96476
Seeing	Day	12% 8% 25% 30% 19% 6%	16903
	Night	13% 6% 24% 35% 18% 3	24749

By Month

Percentage Cloud Cover NW (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	8% 13% 6% 16% 9% 6% 7% 5% 8% 7% 15%	1805
	11th to 20th	Day	8% 11% 4 11% 6% 4 5% 5% 8% 8% 30%	1882
	21st to end	Day	9% 20% 8% 15% 7% 5% 4 3 5% 5% 18%	2154
February	1st to 10th	Day	7% 13% 5% 10% 8% 7% 7% 5% 5% 7% 27%	1520
	11th to 20th	Day	6% 14% 4 10% 7% 7% 6% 4 6% 8% 28%	1480
	21st to end	Day	4 13% 5% 11% 7% 7% 6% 6% 7% 9% 25%	1416
March	1st to 10th	Day	3 8% 5% 14% 8% 7% 7% 5% 8% 10% 25%	3138
	11th to 20th	Day	5% 10% 4 10% 7% 7% 7% 5% 6% 6% 34%	3318
	21st to end	Day	4 8% 3 11% 7% 5% 4 4 6% 7% 42%	4072
April	1st to 10th	Day	5% 11% 3 9% 6% 6% 6% 5% 6% 8% 35%	2356
	11th to 20th	Day	5% 7% 2 8% 6% 6% 6% 5% 8% 8% 40%	2465
	21st to end	Day	10% 10% 3 8% 6% 7% 5% 5% 6% 7% 33%	2693
May	1st to 10th	Day	8% 6% 2 6% 3 4 5% 4 6% 8% 48%	4740
	11th to 20th	Day	13% 10% 4 7% 5% 5% 5% 5% 6% 7% 33%	4840
	21st to end	Day	11% 6% 3 8% 5% 5% 5% 4 6% 8% 39%	5632
June	1st to 10th	Day	13% 8% 3 8% 5% 5% 5% 5% 7% 8% 32%	3230
	11th to 20th	Day	15% 8% 3 8% 6% 5% 5% 4 7% 8% 30%	3230
	21st to end	Day	11% 6% 3 7% 5% 5% 5% 4 7% 10% 36%	3230
July	1st to 10th	Day	6% 4 2 6% 5% 5% 6% 5% 8% 11% 42%	5349
	11th to 20th	Day	7% 4 2 5% 5% 5% 6% 5% 8% 9% 44%	5060
	21st to end	Day	14% 6% 2 6% 5% 5% 5% 4 7% 9% 38%	5486
August	1st to 10th	Day	6% 4 2 5% 4 5% 5% 3 6% 8% 51%	4708
	11th to 20th	Day	9% 6% 2 7% 5% 5% 6% 4 8% 9% 40%	4330
	21st to end	Day	12% 5% 2 6% 5% 5% 6% 5% 7% 7% 38%	4656
September	1st to 10th	Day	14% 5% 2 6% 4 4 4 4 6% 9% 40%	2394
	11th to 20th	Day	9% 8% 2 8% 5% 3 5% 4 6% 8% 42%	2184
	21st to end	Day	10% 8% 3 8% 5% 5% 5% 4 7% 9% 38%	2090
October	1st to 10th	Day	13% 10% 4 8% 6% 5% 5% 4 7% 7% 32%	1889
	11th to 20th	Day	10% 11% 3 8% 6% 5% 6% 4 6% 7% 32%	1710
	21st to end	Day	10% 17% 4 10% 6% 5% 5% 4 6% 6% 26%	1774
November	1st to 10th	Day	12% 13% 5% 11% 9% 6% 5% 3 5% 7% 25%	1309
	11th to 20th	Day	10% 17% 4 13% 8% 5% 5% 5% 5% 7% 21%	1330
	21st to end	Day	9% 12% 5% 12% 7% 7% 5% 4 6% 7% 25%	1117
December	1st to 10th	Day	8% 15% 6% 11% 9% 7% 5% 4 6% 6% 23%	950
	11th to 20th	Day	7% 17% 7% 13% 8% 7% 6% 3 6% 7% 21%	1199
	21st to end	Day	6% 10% 4 9% 6% 6% 6% 4 7% 7% 35%	1738
January	1st to 10th	Night	6% 15% 7% 17% 10% 8% 7% 5% 6% 6% 15%	5138
	11th to 20th	Night	6% 11% 4 9% 7% 6% 7% 6% 10% 9% 28%	5016
	21st to end	Night	7% 19% 6% 16% 8% 6% 5% 3 4 5% 19%	5502
February	1st to 10th	Night	5% 10% 5% 12% 6% 6% 6% 4 6% 7% 33%	2679
	11th to 20th	Night	6% 15% 4 10% 7% 4 5% 5% 5% 7% 32%	2586
	21st to end	Night	4 10% 4 12% 6% 7% 6% 5% 6% 8% 31%	2034
March	1st to 10th	Night	3 9% 5% 11% 6% 6% 6% 4 6% 8% 36%	3736
	11th to 20th	Night	5% 10% 5% 11% 6% 6% 6% 5% 7% 8% 29%	3661
	21st to end	Night	3 8% 4 13% 6% 5% 4 3 5% 6% 44%	3581
April	1st to 10th	Night	6% 12% 4 9% 6% 5% 6% 5% 7% 7% 33%	1824
	11th to 20th	Night	7% 9% 4 8% 5% 5% 6% 5% 8% 7% 36%	1663
	21st to end	Night	11% 10% 4 8% 6% 5% 6% 4 7% 9% 30%	1487
May	1st to 10th	Night	10% 8% 2 6% 5% 5% 5% 4 7% 8% 41%	2220
	11th to 20th	Night	10% 7% 3 8% 6% 6% 6% 5% 8% 9% 32%	2055
	21st to end	Night	12% 7% 2 6% 5% 4 5% 5% 8% 9% 36%	1940
June	1st to 10th	Night	14% 8% 3 7% 6% 6% 8% 7% 5% 7% 29%	950
	11th to 20th	Night	15% 7% 2 8% 5% 4 6% 5% 7% 7% 36%	950
	21st to end	Night	10% 6% 3 7% 6% 4 6% 4 9% 8% 38%	950
July	1st to 10th	Night	7% 5% 2 7% 5% 6% 7% 4 9% 10% 36%	1607
	11th to 20th	Night	10% 5% 2 6% 4 4 5% 4 6% 8% 44%	1900
	21st to end	Night	10% 5% 2 5% 4 5% 5% 5% 9% 11% 41%	2066
August	1st to 10th	Night	6% 3 1 4 4 4 5% 5% 6% 8% 53%	2219
	11th to 20th	Night	7% 5% 3 8% 5% 4 5% 4 7% 8% 45%	2497
	21st to end	Night	10% 6% 2 6% 4 5% 4 4 7% 9% 41%	3006
September	1st to 10th	Night	13% 5% 3 7% 5% 4 4 4 7% 8% 39%	1785
	11th to 20th	Night	12% 7% 3 7% 5% 5% 5% 5% 6% 7% 38%	1995
	21st to end	Night	11% 6% 3 7% 6% 5% 5% 4 6% 9% 37%	2090
October	1st to 10th	Night	10% 8% 3 8% 5% 5% 5% 4 7% 8% 37%	2290
	11th to 20th	Night	8% 10% 3 9% 5% 5% 6% 4 7% 8% 34%	2470
	21st to end	Night	10% 17% 4 11% 6% 5% 4 4 6% 7% 27%	2800
November	1st to 10th	Night	12% 15% 5% 11% 6% 5% 5% 4 6% 7% 26%	2791
	11th to 20th	Night	12% 15% 5% 13% 7% 6% 5% 3 6% 7% 21%	2850
	21st to end	Night	9% 15% 6% 13% 7% 5% 4 3 6% 7% 25%	3062
December	1st to 10th	Night	8% 12% 6% 11% 9% 7% 6% 5% 6% 8% 22%	3230
	11th to 20th	Night	9% 16% 4 12% 7% 6% 6% 4 5% 6% 24%	3993
	21st to end	Night	5% 9% 4 10% 6% 5% 6% 4 7% 8% 36%	5918

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	61% 9% 12% 15% 4	1805
	11th to 20th	Day	48% 9% 14% 19% 10%	1900
	21st to end	Day	67% 7% 12% 10% 4	2154
February	1st to 10th	Day	54% 8% 12% 16% 10%	1520
	11th to 20th	Day	51% 8% 19% 17% 5%	1488
	21st to end	Day	51% 12% 15% 17% 6%	1416
March	1st to 10th	Day	49% 10% 17% 21% 3	3138
	11th to 20th	Day	47% 9% 18% 22% 4	3319
	21st to end	Day	39% 8% 16% 24% 13% 1	4072
April	1st to 10th	Day	44% 9% 17% 20% 10% 1	2356
	11th to 20th	Day	38% 8% 14% 26% 13% 1	2465
	21st to end	Day	47% 9% 16% 19% 9%	2693
May	1st to 10th	Day	31% 7% 15% 28% 19% 1	4740
	11th to 20th	Day	46% 8% 11% 23% 11% 1	4844
	21st to end	Day	40% 8% 14% 22% 15% 1	5633
June	1st to 10th	Day	45% 9% 16% 19% 9% 1	3230
	11th to 20th	Day	48% 10% 16% 20% 6%	3230
	21st to end	Day	41% 12% 18% 23% 7%	3230
July	1st to 10th	Day	31% 10% 26% 29% 3	5265
	11th to 20th	Day	32% 10% 22% 27% 8%	4973
	21st to end	Day	39% 8% 21% 28% 3	5313
August	1st to 10th	Day	29% 10% 20% 36% 6%	4689
	11th to 20th	Day	37% 10% 20% 23% 9% 1	4372
	21st to end	Day	43% 9% 27% 20% 2	4655
September	1st to 10th	Day	40% 10% 25% 20% 5%	2394
	11th to 20th	Day	38% 8% 25% 27% 2	2184
	21st to end	Day	41% 10% 21% 24% 4	2090
October	1st to 10th	Day	49% 8% 17% 20% 5%	1889
	11th to 20th	Day	48% 10% 20% 19% 4	1710
	21st to end	Day	57% 10% 16% 14% 3	1774
November	1st to 10th	Day	57% 9% 16% 14% 3	1309
	11th to 20th	Day	60% 11% 15% 13% 2	1330
	21st to end	Day	57% 9% 15% 16% 3	1117
December	1st to 10th	Day	59% 10% 14% 12% 5%	950
	11th to 20th	Day	62% 7% 11% 20% 1	1200
	21st to end	Day	44% 9% 14% 25% 8%	1738
January	1st to 10th	Night	65% 9% 10% 12% 4	5138
	11th to 20th	Night	47% 9% 13% 21% 9% 1	5060
	21st to end	Night	62% 10% 12% 12% 4	5502
February	1st to 10th	Night	48% 6% 17% 19% 10%	2679
	11th to 20th	Night	49% 7% 17% 21% 6%	2588
	21st to end	Night	48% 9% 16% 22% 5%	2034
March	1st to 10th	Night	44% 6% 16% 26% 7%	3736
	11th to 20th	Night	48% 8% 17% 23% 3	3661
	21st to end	Night	39% 7% 11% 29% 14% 1	3581
April	1st to 10th	Night	45% 9% 13% 21% 10% 2	1824
	11th to 20th	Night	43% 7% 12% 21% 16% 2	1663
	21st to end	Night	47% 9% 13% 20% 11% 1	1487
May	1st to 10th	Night	36% 7% 12% 25% 17% 2	2220
	11th to 20th	Night	42% 10% 11% 20% 16% 1	2055
	21st to end	Night	38% 10% 17% 19% 16% 1	1940
June	1st to 10th	Night	48% 10% 11% 21% 9% 1	950
	11th to 20th	Night	45% 10% 15% 21% 8% 1	950
	21st to end	Night	39% 12% 17% 24% 8% 1	950
July	1st to 10th	Night	37% 10% 21% 23% 8%	1582
	11th to 20th	Night	35% 8% 18% 29% 9%	1864
	21st to end	Night	34% 9% 20% 33% 5%	2000
August	1st to 10th	Night	26% 9% 17% 41% 7%	2213
	11th to 20th	Night	35% 8% 19% 24% 13% 1	2521
	21st to end	Night	38% 8% 26% 24% 3	3006
September	1st to 10th	Night	40% 10% 20% 23% 7%	1785
	11th to 20th	Night	42% 10% 18% 24% 6%	1995
	21st to end	Night	42% 8% 20% 22% 8%	2090
October	1st to 10th	Night	43% 9% 18% 23% 7% 1	2290
	11th to 20th	Night	45% 11% 20% 20% 5%	2470
	21st to end	Night	55% 9% 17% 16% 3	2800
November	1st to 10th	Night	57% 8% 16% 17% 2	2791
	11th to 20th	Night	60% 10% 14% 15% 2	2850
	21st to end	Night	57% 7% 15% 16% 3 1	3062
December	1st to 10th	Night	57% 8% 16% 13% 5%	3230
	11th to 20th	Night	58% 8% 15% 15% 4	3991
	21st to end	Night	42% 9% 19% 22% 8%	5918

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	9% 9% 24% 37% 17% 4	180
	11th to 20th	Day	21% 7% 21% 37% 13% 1	180
	21st to end	Day	17% 8% 27% 35% 10% 3	198
February	1st to 10th	Day	11% 11% 28% 29% 13% 7%	180
	11th to 20th	Day	12% 7% 29% 33% 14% 6%	180
	21st to end	Day	6% 11% 29% 30% 20% 4	254
March	1st to 10th	Day	5% 11% 27% 30% 22% 4	460
	11th to 20th	Day	9% 11% 33% 34% 9% 3	460
	21st to end	Day	9% 11% 30% 33% 15% 2	506
April	1st to 10th	Day	8% 13% 35% 29% 12% 2	460
	11th to 20th	Day	8% 7% 33% 32% 16% 4	452
	21st to end	Day	13% 14% 27% 29% 16% 1	493
May	1st to 10th	Day	10% 13% 26% 30% 16% 4	653
	11th to 20th	Day	13% 11% 24% 27% 20% 6%	754
	21st to end	Day	12% 6% 21% 33% 23% 5%	940
June	1st to 10th	Day	16% 9% 26% 29% 17% 3	870
	11th to 20th	Day	17% 6% 23% 28% 20% 5%	870
	21st to end	Day	10% 5% 18% 31% 27% 8%	870
July	1st to 10th	Day	10% 6% 21% 30% 26% 6%	856
	11th to 20th	Day	11% 5% 18% 31% 26% 9%	852
	21st to end	Day	13% 5% 17% 27% 29% 10%	947
August	1st to 10th	Day	12% 3 16% 29% 28% 11%	677
	11th to 20th	Day	13% 9% 30% 29% 14% 5%	477
	21st to end	Day	17% 6% 24% 30% 17% 7%	539
September	1st to 10th	Day	17% 8% 28% 26% 14% 8%	490
	11th to 20th	Day	10% 7% 25% 28% 23% 8%	490
	21st to end	Day	11% 9% 30% 30% 16% 4	490
October	1st to 10th	Day	17% 11% 27% 26% 15% 3	412
	11th to 20th	Day	16% 7% 33% 30% 11% 3	300
	21st to end	Day	19% 10% 30% 26% 10% 4	313
November	1st to 10th	Day	14% 5% 27% 33% 16% 4	182
	11th to 20th	Day	14% 7% 28% 37% 12% 3	180
	21st to end	Day	16% 9% 28% 29% 16% 1	180
December	1st to 10th	Day	13% 6% 18% 38% 23% 2	180
	11th to 20th	Day	8% 11% 25% 41% 11% 4	180
	21st to end	Day	8% 6% 24% 31% 24% 8%	198
January	1st to 10th	Night	15% 6% 23% 36% 18% 3	1040
	11th to 20th	Night	15% 7% 25% 36% 14% 2	1040
	21st to end	Night	15% 10% 30% 32% 12% 2	1126
February	1st to 10th	Night	8% 6% 27% 35% 19% 5%	779
	11th to 20th	Night	13% 7% 24% 36% 17% 3	744
	21st to end	Night	7% 5% 26% 41% 18% 4	628
March	1st to 10th	Night	6% 8% 26% 33% 23% 4	760
	11th to 20th	Night	13% 8% 29% 35% 14% 2	760
	21st to end	Night	9% 5% 26% 40% 19% 2	836
April	1st to 10th	Night	12% 9% 26% 34% 19% 2	684
	11th to 20th	Night	11% 6% 29% 36% 17% 2	535
	21st to end	Night	14% 8% 28% 33% 15% 1	380
May	1st to 10th	Night	13% 6% 25% 37% 17% 2	380
	11th to 20th	Night	10% 9% 26% 33% 21% 2	374
	21st to end	Night	12% 6% 18% 38% 24% 1	411
June	1st to 10th	Night	16% 5% 21% 34% 22% 2	380
	11th to 20th	Night	17% 3 18% 32% 29% 1	380
	21st to end	Night	10% 3 15% 40% 25% 6%	380
July	1st to 10th	Night	11% 4 15% 39% 29% 2	370
	11th to 20th	Night	13% 2 16% 36% 29% 5%	368
	21st to end	Night	9% 3 15% 32% 36% 5%	416
August	1st to 10th	Night	9% 4 12% 37% 31% 7%	378
	11th to 20th	Night	8% 3 18% 45% 23% 2	376
	21st to end	Night	15% 2 20% 34% 26% 2	539
September	1st to 10th	Night	16% 3 19% 36% 22% 3	645
	11th to 20th	Night	14% 5% 19% 37% 20% 4	760
	21st to end	Night	13% 6% 26% 35% 17% 3	760
October	1st to 10th	Night	13% 7% 29% 34% 15% 2	760
	11th to 20th	Night	14% 6% 29% 35% 14% 2	760
	21st to end	Night	20% 9% 27% 31% 12% 1	891
November	1st to 10th	Night	17% 6% 26% 33% 16% 2	931
	11th to 20th	Night	19% 7% 25% 33% 16% 1	950
	21st to end	Night	16% 6% 30% 33% 13% 2	1004
December	1st to 10th	Night	14% 6% 24% 38% 16% 3	1040
	11th to 20th	Night	14% 8% 28% 33% 14% 3	1040
	21st to end	Night	11% 5% 20% 36% 23% 4	1144

Page generated at 2024-10-29 23:23:00. Version ac07

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