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 2024-03-06.

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	10% 9% 4 7% 7% 4 6% 6% 6% 8% 34%	77131
	Night	8% 10% 5% 9% 8% 4 6% 6% 6% 8% 30%	82325
Transparency	Day	46% 10% 18% 20% 6%	76800
	Night	49% 9% 16% 19% 6%	82236
Seeing	Day	12% 8% 25% 30% 19% 6%	15790
	Night	13% 6% 24% 35% 18% 3	24063

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% 12% 6% 14% 10% 5% 7% 8% 8% 7% 15%	1805
	11th to 20th	Day	8% 10% 4 11% 7% 3 5% 6% 7% 9% 30%	1882
	21st to end	Day	9% 19% 8% 13% 10% 4 5% 4 5% 6% 18%	2154
February	1st to 10th	Day	7% 12% 5% 9% 8% 6% 8% 6% 5% 7% 27%	1520
	11th to 20th	Day	7% 12% 5% 9% 8% 5% 6% 6% 5% 8% 29%	1480
	21st to end	Day	4 11% 6% 10% 8% 5% 7% 8% 7% 9% 25%	1416
March	1st to 10th	Day	4 9% 4 10% 10% 5% 7% 6% 7% 9% 29%	1851
	11th to 20th	Day	8% 10% 6% 9% 6% 3 7% 4 5% 6% 34%	1873
	21st to end	Day	6% 11% 4 7% 7% 3 5% 5% 6% 8% 37%	2322
April	1st to 10th	Day	6% 9% 5% 8% 7% 4 6% 6% 6% 8% 35%	2232
	11th to 20th	Day	5% 7% 3 7% 7% 4 7% 6% 9% 8% 38%	2333
	21st to end	Day	10% 9% 3 7% 7% 5% 6% 6% 6% 7% 33%	2551
May	1st to 10th	Day	8% 7% 3 6% 5% 3 5% 6% 7% 9% 41%	2700
	11th to 20th	Day	11% 7% 3 5% 5% 4 5% 5% 6% 8% 42%	2730
	21st to end	Day	10% 5% 3 6% 6% 4 5% 5% 6% 8% 42%	3178
June	1st to 10th	Day	13% 6% 3 6% 7% 3 6% 6% 7% 9% 34%	3060
	11th to 20th	Day	15% 7% 3 7% 6% 3 5% 6% 7% 8% 31%	3060
	21st to end	Day	12% 6% 3 5% 6% 4 6% 5% 7% 10% 35%	3060
July	1st to 10th	Day	11% 6% 3 7% 7% 4 6% 6% 6% 9% 36%	3043
	11th to 20th	Day	11% 5% 3 6% 6% 4 7% 6% 8% 9% 35%	2880
	21st to end	Day	11% 5% 3 6% 5% 3 6% 5% 7% 9% 39%	3135
August	1st to 10th	Day	10% 5% 2 5% 6% 4 6% 5% 7% 10% 40%	2688
	11th to 20th	Day	11% 6% 3 6% 5% 4 6% 6% 7% 9% 38%	2475
	21st to end	Day	14% 6% 2 5% 6% 4 5% 6% 7% 8% 37%	2657
September	1st to 10th	Day	15% 5% 2 5% 5% 3 5% 4 6% 9% 41%	2268
	11th to 20th	Day	10% 7% 3 7% 6% 2 4 5% 6% 8% 42%	2070
	21st to end	Day	10% 7% 3 7% 6% 4 5% 5% 6% 9% 39%	1980
October	1st to 10th	Day	13% 9% 4 7% 7% 3 5% 5% 7% 8% 32%	1791
	11th to 20th	Day	10% 10% 4 8% 7% 4 7% 5% 6% 7% 32%	1620
	21st to end	Day	11% 17% 4 9% 7% 4 5% 6% 6% 6% 26%	1681
November	1st to 10th	Day	12% 11% 6% 10% 10% 4 6% 5% 5% 7% 25%	1302
	11th to 20th	Day	11% 15% 5% 12% 9% 4 5% 6% 5% 7% 21%	1330
	21st to end	Day	10% 11% 6% 11% 8% 5% 6% 6% 6% 7% 25%	1117
December	1st to 10th	Day	8% 14% 6% 11% 9% 6% 6% 5% 6% 6% 23%	950
	11th to 20th	Day	7% 16% 7% 11% 10% 4 6% 5% 5% 8% 21%	1199
	21st to end	Day	6% 10% 4 8% 8% 5% 6% 5% 7% 6% 35%	1738
January	1st to 10th	Night	6% 14% 8% 14% 12% 6% 8% 6% 6% 6% 15%	5138
	11th to 20th	Night	6% 11% 4 8% 8% 4 6% 7% 10% 9% 28%	5016
	21st to end	Night	7% 19% 6% 14% 11% 4 6% 4 4 5% 20%	5502
February	1st to 10th	Night	5% 10% 5% 11% 7% 4 7% 5% 6% 8% 33%	2679
	11th to 20th	Night	6% 13% 5% 9% 8% 3 5% 5% 5% 8% 32%	2586
	21st to end	Night	4 9% 5% 10% 7% 5% 7% 6% 6% 8% 31%	2034
March	1st to 10th	Night	5% 7% 5% 10% 7% 3 6% 5% 6% 7% 39%	2225
	11th to 20th	Night	8% 11% 6% 9% 7% 4 6% 6% 6% 6% 30%	2086
	21st to end	Night	6% 10% 4 7% 6% 4 5% 5% 6% 7% 38%	2034
April	1st to 10th	Night	7% 10% 4 8% 7% 4 6% 6% 7% 8% 34%	1728
	11th to 20th	Night	7% 9% 4 7% 5% 4 6% 7% 7% 8% 36%	1575
	21st to end	Night	11% 9% 4 7% 7% 4 6% 6% 7% 10% 29%	1409
May	1st to 10th	Night	10% 8% 3 6% 7% 3 7% 6% 7% 9% 33%	1260
	11th to 20th	Night	7% 5% 2 7% 5% 4 6% 5% 8% 11% 39%	1165
	21st to end	Night	12% 6% 3 5% 6% 2 5% 6% 7% 9% 40%	1094
June	1st to 10th	Night	13% 7% 3 6% 7% 4 8% 8% 6% 8% 31%	900
	11th to 20th	Night	15% 6% 3 7% 6% 3 5% 6% 6% 7% 36%	900
	21st to end	Night	11% 6% 3 5% 8% 2 6% 5% 8% 8% 37%	900
July	1st to 10th	Night	11% 6% 3 7% 6% 5% 6% 5% 7% 10% 34%	913
	11th to 20th	Night	12% 5% 3 7% 5% 4 6% 6% 7% 11% 35%	1080
	21st to end	Night	9% 5% 3 6% 4 4 5% 6% 9% 10% 39%	1182
August	1st to 10th	Night	10% 5% 3 4 5% 4 7% 7% 8% 8% 41%	1248
	11th to 20th	Night	6% 3 3 7% 6% 3 5% 6% 8% 8% 46%	1424
	21st to end	Night	12% 6% 2 5% 5% 5% 4 5% 6% 8% 41%	1698
September	1st to 10th	Night	14% 5% 4 6% 6% 3 4 5% 6% 7% 40%	1691
	11th to 20th	Night	13% 6% 3 5% 6% 4 5% 6% 6% 7% 39%	1890
	21st to end	Night	11% 6% 3 6% 6% 4 6% 6% 6% 9% 37%	1980
October	1st to 10th	Night	10% 8% 4 6% 7% 3 5% 5% 7% 8% 37%	2168
	11th to 20th	Night	8% 10% 4 8% 5% 4 5% 6% 7% 8% 34%	2340
	21st to end	Night	10% 16% 4 9% 8% 4 4 5% 6% 7% 27%	2652
November	1st to 10th	Night	12% 13% 6% 10% 7% 4 4 5% 6% 7% 26%	2775
	11th to 20th	Night	12% 14% 6% 12% 9% 4 5% 4 6% 8% 21%	2850
	21st to end	Night	10% 14% 6% 11% 8% 4 5% 4 5% 8% 25%	3062
December	1st to 10th	Night	8% 11% 6% 10% 11% 6% 6% 6% 6% 8% 23%	3230
	11th to 20th	Night	9% 15% 5% 10% 9% 5% 6% 6% 5% 7% 24%	3993
	21st to end	Night	5% 8% 4 8% 7% 4 6% 5% 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% 9% 17% 21% 4	1851
	11th to 20th	Day	50% 6% 17% 22% 5%	1874
	21st to end	Day	43% 9% 18% 24% 6% 1	2322
April	1st to 10th	Day	45% 9% 17% 20% 9% 1	2232
	11th to 20th	Day	39% 9% 14% 26% 11% 1	2333
	21st to end	Day	48% 9% 16% 19% 8%	2551
May	1st to 10th	Day	38% 9% 17% 24% 12%	2700
	11th to 20th	Day	38% 8% 12% 24% 16% 1	2734
	21st to end	Day	38% 8% 13% 24% 15% 1	3179
June	1st to 10th	Day	44% 9% 16% 20% 9% 1	3060
	11th to 20th	Day	47% 10% 16% 20% 6%	3060
	21st to end	Day	41% 13% 19% 22% 5%	3060
July	1st to 10th	Day	42% 12% 20% 23% 3	2959
	11th to 20th	Day	41% 13% 27% 17% 2	2793
	21st to end	Day	38% 12% 25% 24% 2	2961
August	1st to 10th	Day	37% 13% 27% 21% 2	2669
	11th to 20th	Day	40% 13% 24% 20% 3	2475
	21st to end	Day	44% 11% 23% 20% 3	2657
September	1st to 10th	Day	40% 10% 25% 20% 5%	2268
	11th to 20th	Day	39% 9% 25% 26% 2	2070
	21st to end	Day	40% 10% 22% 24% 4	1980
October	1st to 10th	Day	50% 9% 17% 20% 5%	1791
	11th to 20th	Day	48% 10% 20% 18% 4	1620
	21st to end	Day	57% 11% 15% 14% 3	1681
November	1st to 10th	Day	57% 9% 17% 14% 3	1302
	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	43% 6% 17% 24% 9%	2225
	11th to 20th	Night	53% 6% 13% 23% 5%	2086
	21st to end	Night	42% 7% 14% 27% 9%	2034
April	1st to 10th	Night	45% 9% 13% 21% 10% 2	1728
	11th to 20th	Night	43% 8% 12% 22% 14% 2	1575
	21st to end	Night	48% 9% 13% 19% 10% 1	1409
May	1st to 10th	Night	43% 8% 11% 21% 15% 2	1260
	11th to 20th	Night	36% 8% 12% 24% 18% 2	1165
	21st to end	Night	38% 6% 12% 23% 20% 1	1094
June	1st to 10th	Night	47% 10% 12% 22% 9% 1	900
	11th to 20th	Night	45% 11% 15% 21% 8% 1	900
	21st to end	Night	40% 12% 17% 23% 7% 1	900
July	1st to 10th	Night	41% 12% 18% 24% 6%	888
	11th to 20th	Night	42% 11% 25% 20% 2	1044
	21st to end	Night	34% 12% 24% 28% 2	1116
August	1st to 10th	Night	36% 12% 24% 23% 6%	1242
	11th to 20th	Night	33% 10% 26% 25% 5%	1424
	21st to end	Night	39% 10% 21% 24% 5%	1698
September	1st to 10th	Night	40% 10% 20% 22% 7%	1691
	11th to 20th	Night	41% 10% 19% 24% 6%	1890
	21st to end	Night	42% 8% 20% 23% 8%	1980
October	1st to 10th	Night	43% 9% 18% 22% 7% 1	2168
	11th to 20th	Night	44% 11% 20% 20% 5%	2340
	21st to end	Night	55% 9% 17% 15% 3	2652
November	1st to 10th	Night	57% 8% 16% 17% 2	2775
	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% 10% 27% 31% 22% 4	441
	11th to 20th	Day	10% 10% 32% 34% 10% 4	420
	21st to end	Day	10% 11% 29% 33% 14% 2	462
April	1st to 10th	Day	7% 12% 35% 30% 13% 2	420
	11th to 20th	Day	8% 7% 33% 32% 16% 3	412
	21st to end	Day	13% 15% 29% 29% 14%	451
May	1st to 10th	Day	10% 13% 27% 31% 15% 4	603
	11th to 20th	Day	11% 11% 24% 27% 21% 6%	699
	21st to end	Day	12% 6% 21% 32% 24% 5%	874
June	1st to 10th	Day	15% 8% 27% 29% 19% 3	810
	11th to 20th	Day	17% 6% 24% 28% 20% 5%	810
	21st to end	Day	11% 5% 19% 30% 27% 8%	810
July	1st to 10th	Day	11% 6% 21% 29% 26% 6%	796
	11th to 20th	Day	11% 5% 18% 31% 25% 9%	792
	21st to end	Day	12% 4 17% 27% 29% 11%	881
August	1st to 10th	Day	13% 4 16% 29% 27% 12%	628
	11th to 20th	Day	13% 10% 30% 29% 14% 5%	437
	21st to end	Day	17% 5% 23% 28% 18% 8%	495
September	1st to 10th	Day	18% 8% 26% 26% 14% 8%	450
	11th to 20th	Day	11% 7% 25% 27% 23% 7%	450
	21st to end	Day	11% 10% 28% 31% 16% 5%	450
October	1st to 10th	Day	19% 11% 25% 27% 15% 3	377
	11th to 20th	Day	14% 7% 34% 31% 12% 3	270
	21st to end	Day	21% 11% 28% 26% 10% 5%	282
November	1st to 10th	Day	14% 6% 27% 33% 16% 3	180
	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	7% 8% 25% 34% 23% 4	742
	11th to 20th	Night	13% 7% 28% 36% 15% 2	720
	21st to end	Night	10% 5% 26% 39% 19% 2	792
April	1st to 10th	Night	12% 9% 24% 34% 19% 2	648
	11th to 20th	Night	11% 6% 29% 35% 17% 2	507
	21st to end	Night	14% 9% 28% 34% 15% 1	360
May	1st to 10th	Night	12% 6% 26% 37% 17% 2	360
	11th to 20th	Night	8% 8% 27% 33% 21% 2	354
	21st to end	Night	12% 5% 19% 37% 25% 2	389
June	1st to 10th	Night	14% 5% 21% 35% 23% 3	360
	11th to 20th	Night	17% 3 18% 32% 28% 1	360
	21st to end	Night	11% 4 16% 38% 26% 6%	360
July	1st to 10th	Night	12% 4 15% 38% 29% 3	350
	11th to 20th	Night	13% 1 16% 36% 28% 5%	348
	21st to end	Night	9% 3 14% 31% 37% 5%	394
August	1st to 10th	Night	9% 4 12% 36% 31% 7%	358
	11th to 20th	Night	8% 3 18% 46% 23% 2	356
	21st to end	Night	16% 2 19% 33% 27% 3	510
September	1st to 10th	Night	16% 3 19% 34% 23% 4	611
	11th to 20th	Night	15% 5% 20% 37% 20% 4	720
	21st to end	Night	13% 6% 26% 35% 17% 3	720
October	1st to 10th	Night	13% 7% 29% 34% 15% 2	720
	11th to 20th	Night	14% 6% 28% 36% 14% 2	720
	21st to end	Night	20% 8% 27% 31% 13% 1	844
November	1st to 10th	Night	17% 6% 26% 33% 16% 2	925
	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 2024-03-03 04:29:00. Version ac07

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