Amqui
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Amqui clear sky chart from 2005-11-06 to 2025-05-26.

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	16% 11% 4 10% 7% 6% 5% 4 5% 6% 25%	113538
	Night	14% 12% 4 10% 8% 7% 6% 4 5% 6% 24%	115843
Transparency	Day	60% 4 11% 17% 7% 1	117009
	Night	62% 4 11% 16% 7%	120511
Seeing	Day	26% 13% 27% 22% 10% 2	16761
	Night	24% 11% 26% 28% 10% 1	24711

By Month

Percentage Cloud Cover NE (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	13% 21% 7% 17% 12% 10% 6% 3 4 3 6%	3157
	11th to 20th	Day	9% 10% 6% 19% 17% 11% 5% 4 4 4 9%	3309
	21st to end	Day	4 6% 3 13% 8% 12% 11% 11% 9% 6% 17%	3960
February	1st to 10th	Day	7% 13% 4 10% 10% 10% 10% 6% 7% 5% 19%	1750
	11th to 20th	Day	9% 16% 7% 13% 9% 8% 7% 6% 5% 4 17%	1753
	21st to end	Day	8% 13% 5% 12% 9% 9% 7% 3 5% 7% 21%	1601
March	1st to 10th	Day	15% 14% 5% 12% 8% 6% 8% 4 5% 6% 16%	4585
	11th to 20th	Day	16% 17% 5% 9% 6% 7% 7% 5% 6% 7% 16%	4980
	21st to end	Day	19% 17% 6% 11% 6% 5% 3 3 4 4 21%	5466
April	1st to 10th	Day	18% 14% 5% 10% 6% 6% 5% 4 4 6% 24%	2425
	11th to 20th	Day	15% 14% 3 9% 6% 4 4 4 5% 6% 30%	2572
	21st to end	Day	21% 13% 4 9% 5% 4 3 3 4 5% 28%	2600
May	1st to 10th	Day	18% 15% 4 10% 6% 4 4 4 4 5% 25%	4258
	11th to 20th	Day	18% 10% 3 9% 5% 5% 5% 4 6% 6% 30%	4714
	21st to end	Day	19% 10% 4 9% 5% 5% 4 4 5% 7% 28%	5260
June	1st to 10th	Day	22% 10% 3 7% 6% 5% 4 3 4 6% 30%	2850
	11th to 20th	Day	20% 7% 2 6% 5% 4 4 4 6% 7% 33%	2850
	21st to end	Day	22% 9% 4 7% 5% 6% 5% 4 7% 7% 25%	2850
July	1st to 10th	Day	15% 8% 3 9% 6% 6% 5% 4 6% 7% 31%	4760
	11th to 20th	Day	14% 7% 3 7% 5% 6% 6% 5% 6% 8% 33%	4760
	21st to end	Day	12% 6% 2 6% 4 6% 6% 5% 7% 9% 38%	4956
August	1st to 10th	Day	14% 7% 3 8% 5% 5% 5% 5% 6% 8% 34%	4176
	11th to 20th	Day	16% 8% 3 9% 6% 6% 6% 5% 6% 8% 27%	4045
	21st to end	Day	16% 7% 3 7% 5% 4 5% 4 6% 8% 36%	4532
September	1st to 10th	Day	18% 7% 3 7% 5% 4 4 4 5% 6% 36%	2308
	11th to 20th	Day	19% 7% 2 5% 4 4 3 3 4 6% 43%	2090
	21st to end	Day	17% 10% 3 7% 4 5% 4 3 5% 7% 34%	2090
October	1st to 10th	Day	17% 10% 3 8% 6% 4 3 4 5% 5% 34%	1956
	11th to 20th	Day	22% 12% 4 9% 4 5% 4 4 6% 6% 26%	1879
	21st to end	Day	22% 17% 5% 8% 5% 4 4 4 4 5% 23%	1881
November	1st to 10th	Day	16% 16% 5% 10% 6% 6% 5% 4 5% 4 22%	1651
	11th to 20th	Day	18% 16% 6% 14% 6% 5% 5% 2 5% 6% 18%	1600
	21st to end	Day	19% 17% 5% 15% 11% 5% 4 4 4 5% 14%	1540
December	1st to 10th	Day	13% 15% 5% 17% 15% 7% 5% 3 4 4 12%	2280
	11th to 20th	Day	16% 14% 5% 16% 11% 6% 5% 4 4 4 16%	2618
	21st to end	Day	12% 16% 5% 16% 10% 8% 6% 3 4 5% 16%	3476
January	1st to 10th	Night	11% 20% 8% 17% 11% 10% 5% 4 4 4 5%	6808
	11th to 20th	Night	9% 14% 5% 17% 15% 9% 6% 4 5% 4 12%	6572
	21st to end	Night	3 8% 4 12% 7% 9% 13% 10% 7% 7% 21%	6996
February	1st to 10th	Night	7% 13% 6% 10% 9% 10% 8% 6% 7% 6% 19%	2649
	11th to 20th	Night	11% 15% 5% 12% 7% 8% 8% 5% 6% 5% 19%	2533
	21st to end	Night	9% 13% 4 10% 7% 10% 6% 4 6% 6% 24%	2025
March	1st to 10th	Night	15% 14% 4 9% 7% 6% 9% 4 4 4 23%	5255
	11th to 20th	Night	18% 16% 5% 11% 7% 6% 6% 4 5% 5% 18%	4979
	21st to end	Night	21% 17% 4 9% 9% 5% 3 2 3 4 22%	5466
April	1st to 10th	Night	19% 14% 4 9% 6% 5% 5% 4 4 5% 26%	1971
	11th to 20th	Night	20% 10% 3 7% 4 4 4 4 6% 5% 34%	1778
	21st to end	Night	21% 11% 3 7% 3 3 4 4 6% 5% 34%	1800
May	1st to 10th	Night	16% 12% 3 8% 5% 4 5% 4 6% 7% 29%	2902
	11th to 20th	Night	17% 9% 3 8% 5% 5% 5% 5% 6% 7% 31%	2438
	21st to end	Night	14% 8% 4 9% 5% 6% 6% 5% 8% 9% 28%	2442
June	1st to 10th	Night	20% 9% 3 8% 5% 5% 4 4 6% 6% 32%	1330
	11th to 20th	Night	18% 7% 2 5% 4 3 5% 4 7% 7% 37%	1330
	21st to end	Night	21% 7% 3 9% 5% 5% 5% 4 4 5% 30%	1330
July	1st to 10th	Night	13% 7% 3 7% 5% 5% 5% 5% 7% 7% 36%	2210
	11th to 20th	Night	13% 6% 2 8% 5% 5% 4 4 6% 9% 36%	2210
	21st to end	Night	11% 6% 2 5% 4 4 4 4 6% 8% 45%	2598
August	1st to 10th	Night	15% 6% 3 8% 5% 5% 5% 4 7% 8% 33%	2721
	11th to 20th	Night	12% 8% 3 9% 5% 6% 6% 5% 7% 8% 31%	2782
	21st to end	Night	16% 6% 3 6% 4 4 5% 3 5% 6% 42%	3124
September	1st to 10th	Night	17% 7% 2 6% 4 5% 5% 3 5% 7% 41%	1869
	11th to 20th	Night	16% 7% 2 6% 5% 5% 5% 3 5% 6% 41%	2090
	21st to end	Night	16% 6% 3 5% 4 5% 4 3 4 5% 44%	2090
October	1st to 10th	Night	19% 7% 2 7% 4 4 4 3 4 6% 39%	2223
	11th to 20th	Night	21% 11% 3 7% 5% 5% 5% 4 5% 6% 28%	2299
	21st to end	Night	19% 13% 3 8% 4 5% 5% 4 6% 7% 26%	2717
November	1st to 10th	Night	19% 12% 4 9% 5% 5% 5% 4 5% 6% 26%	2646
	11th to 20th	Night	17% 16% 4 12% 5% 5% 6% 4 4 6% 22%	2800
	21st to end	Night	18% 16% 5% 14% 8% 7% 4 4 6% 4 14%	2857
December	1st to 10th	Night	12% 14% 5% 15% 12% 7% 7% 4 5% 4 15%	4910
	11th to 20th	Night	17% 13% 4 13% 14% 7% 5% 4 4 4 14%	5591
	21st to end	Night	13% 14% 5% 13% 10% 10% 5% 4 5% 7% 13%	7502

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	87% 2 5% 4 1	3158
	11th to 20th	Day	81% 3 7% 6% 3	3336
	21st to end	Day	63% 6% 9% 14% 8%	3960
February	1st to 10th	Day	67% 3 9% 15% 6% 1	1750
	11th to 20th	Day	72% 3 8% 12% 4	1761
	21st to end	Day	66% 2 6% 19% 6%	1601
March	1st to 10th	Day	70% 2 9% 13% 5%	4589
	11th to 20th	Day	68% 5% 9% 14% 4	4980
	21st to end	Day	68% 2 5% 16% 8% 1	5466
April	1st to 10th	Day	63% 1 8% 16% 9% 2	2425
	11th to 20th	Day	56% 2 8% 22% 11% 1	2572
	21st to end	Day	60% 2 7% 19% 11% 2	2600
May	1st to 10th	Day	64% 1 7% 18% 9% 1	4272
	11th to 20th	Day	56% 2 13% 19% 10% 1	4718
	21st to end	Day	57% 2 8% 22% 11% 1	5260
June	1st to 10th	Day	57% 3 8% 18% 11% 2	2850
	11th to 20th	Day	49% 4 13% 19% 13% 2	2850
	21st to end	Day	57% 4 12% 17% 9%	2850
July	1st to 10th	Day	52% 4 13% 22% 9%	4685
	11th to 20th	Day	48% 6% 17% 22% 6%	4679
	21st to end	Day	41% 6% 20% 25% 8%	4798
August	1st to 10th	Day	48% 5% 18% 22% 6%	4162
	11th to 20th	Day	52% 7% 20% 16% 5%	4084
	21st to end	Day	46% 5% 17% 22% 10%	4532
September	1st to 10th	Day	49% 3 14% 24% 9%	2308
	11th to 20th	Day	45% 3 15% 27% 9%	2090
	21st to end	Day	51% 3 11% 25% 9%	2090
October	1st to 10th	Day	54% 5% 14% 20% 6% 1	3242
	11th to 20th	Day	61% 3 12% 21% 3	3095
	21st to end	Day	58% 4 14% 18% 6%	3081
November	1st to 10th	Day	67% 3 12% 13% 5%	1651
	11th to 20th	Day	72% 3 10% 12% 3	1600
	21st to end	Day	77% 2 10% 9% 2	1540
December	1st to 10th	Day	79% 4 9% 8% 1	2280
	11th to 20th	Day	75% 2 6% 11% 6%	2618
	21st to end	Day	75% 3 7% 9% 6%	3476
January	1st to 10th	Night	86% 2 6% 5% 1	6808
	11th to 20th	Night	78% 4 6% 8% 4	6619
	21st to end	Night	62% 4 9% 15% 9% 1	6996
February	1st to 10th	Night	65% 4 7% 15% 8% 1	2649
	11th to 20th	Night	68% 3 10% 13% 6%	2536
	21st to end	Night	62% 3 9% 18% 8%	2025
March	1st to 10th	Night	67% 2 10% 14% 8%	5264
	11th to 20th	Night	69% 4 9% 12% 5%	4980
	21st to end	Night	69% 2 6% 14% 9% 1	5466
April	1st to 10th	Night	63% 2 7% 14% 13% 2	1971
	11th to 20th	Night	53% 2 7% 21% 15% 1	1778
	21st to end	Night	53% 2 8% 22% 14% 1	1800
May	1st to 10th	Night	55% 2 13% 16% 13% 1	2908
	11th to 20th	Night	53% 2 12% 23% 9%	2439
	21st to end	Night	53% 4 9% 25% 8% 1	2443
June	1st to 10th	Night	52% 3 11% 21% 11% 1	1330
	11th to 20th	Night	44% 5% 13% 22% 15% 1	1330
	21st to end	Night	56% 4 11% 18% 11%	1330
July	1st to 10th	Night	46% 6% 14% 26% 8%	2175
	11th to 20th	Night	45% 6% 22% 22% 5%	2168
	21st to end	Night	37% 7% 23% 22% 11%	2515
August	1st to 10th	Night	48% 6% 19% 21% 5%	2711
	11th to 20th	Night	49% 9% 22% 15% 5%	2809
	21st to end	Night	43% 6% 14% 24% 13%	3124
September	1st to 10th	Night	46% 2 13% 29% 10%	1869
	11th to 20th	Night	46% 3 16% 25% 10%	2090
	21st to end	Night	44% 4 12% 25% 14% 1	2090
October	1st to 10th	Night	51% 3 11% 27% 7% 1	3704
	11th to 20th	Night	54% 4 12% 25% 4	3810
	21st to end	Night	53% 6% 16% 19% 5% 1	4467
November	1st to 10th	Night	61% 3 14% 15% 6%	2646
	11th to 20th	Night	69% 3 10% 14% 5%	2800
	21st to end	Night	76% 4 9% 8% 3 1	2857
December	1st to 10th	Night	75% 4 11% 9% 1	4910
	11th to 20th	Night	76% 4 6% 9% 4	5592
	21st to end	Night	73% 3 9% 11% 3 1	7502

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	27% 22% 28% 19% 4 2	200
	11th to 20th	Day	22% 22% 28% 15% 10% 4	200
	21st to end	Day	13% 22% 33% 23% 5% 3	220
February	1st to 10th	Day	21% 17% 32% 20% 8% 2	350
	11th to 20th	Day	19% 23% 33% 18% 6% 1	396
	21st to end	Day	22% 20% 32% 18% 8% 1	390
March	1st to 10th	Day	22% 17% 32% 21% 6% 1	500
	11th to 20th	Day	28% 17% 26% 20% 9% 1	500
	21st to end	Day	29% 17% 26% 18% 8% 3	550
April	1st to 10th	Day	30% 19% 25% 17% 8% 1	500
	11th to 20th	Day	27% 14% 32% 18% 7% 2	492
	21st to end	Day	35% 13% 24% 21% 6% 2	500
May	1st to 10th	Day	34% 12% 27% 19% 5% 2	512
	11th to 20th	Day	28% 11% 25% 23% 11% 2	724
	21st to end	Day	31% 15% 24% 19% 9% 2	760
June	1st to 10th	Day	29% 12% 24% 24% 10% 2	680
	11th to 20th	Day	25% 12% 25% 22% 13% 3	680
	21st to end	Day	25% 8% 26% 27% 10% 3	680
July	1st to 10th	Day	21% 6% 29% 27% 13% 4	670
	11th to 20th	Day	17% 8% 29% 30% 13% 3	668
	21st to end	Day	18% 8% 27% 31% 13% 3	622
August	1st to 10th	Day	19% 9% 29% 26% 13% 4	486
	11th to 20th	Day	18% 8% 29% 29% 14% 3	479
	21st to end	Day	23% 9% 27% 22% 14% 5%	539
September	1st to 10th	Day	23% 12% 28% 21% 11% 5%	490
	11th to 20th	Day	24% 9% 29% 22% 11% 5%	490
	21st to end	Day	26% 13% 25% 18% 13% 4	490
October	1st to 10th	Day	22% 12% 28% 21% 13% 4	419
	11th to 20th	Day	36% 10% 21% 20% 9% 4	390
	21st to end	Day	34% 17% 21% 18% 10% 1	429
November	1st to 10th	Day	31% 15% 28% 18% 6% 2	395
	11th to 20th	Day	29% 15% 28% 19% 8% 1	400
	21st to end	Day	34% 21% 23% 17% 5% 1	340
December	1st to 10th	Day	24% 15% 35% 15% 8% 5%	200
	11th to 20th	Day	26% 28% 27% 16% 4	200
	21st to end	Day	25% 22% 30% 15% 7%	220
January	1st to 10th	Night	23% 12% 30% 27% 6% 1	900
	11th to 20th	Night	23% 15% 28% 27% 7%	857
	21st to end	Night	15% 16% 30% 28% 9% 1	880
February	1st to 10th	Night	17% 15% 31% 28% 8% 1	800
	11th to 20th	Night	24% 12% 33% 23% 9%	783
	21st to end	Night	18% 11% 33% 27% 10% 1	660
March	1st to 10th	Night	22% 11% 29% 30% 7% 1	800
	11th to 20th	Night	26% 14% 28% 22% 9% 1	800
	21st to end	Night	25% 11% 25% 27% 10% 1	880
April	1st to 10th	Night	29% 15% 25% 25% 6%	719
	11th to 20th	Night	26% 11% 24% 29% 9% 1	594
	21st to end	Night	28% 13% 25% 25% 8% 1	600
May	1st to 10th	Night	28% 10% 24% 30% 8% 1	600
	11th to 20th	Night	24% 9% 26% 29% 11% 1	509
	21st to end	Night	22% 8% 28% 33% 10%	423
June	1st to 10th	Night	22% 6% 19% 41% 11% 1	380
	11th to 20th	Night	21% 4 23% 35% 16% 1	380
	21st to end	Night	22% 5% 25% 34% 12% 1	380
July	1st to 10th	Night	20% 4 24% 36% 15% 1	370
	11th to 20th	Night	18% 3 21% 42% 16%	368
	21st to end	Night	17% 6% 17% 39% 21% 1	416
August	1st to 10th	Night	17% 3 20% 39% 20% 1	502
	11th to 20th	Night	19% 4 16% 39% 21% 1	562
	21st to end	Night	19% 4 20% 37% 18% 3	627
September	1st to 10th	Night	22% 5% 27% 33% 11% 2	620
	11th to 20th	Night	21% 7% 21% 34% 16% 2	760
	21st to end	Night	21% 7% 26% 32% 13% 1	760
October	1st to 10th	Night	23% 11% 24% 29% 12% 1	760
	11th to 20th	Night	29% 8% 24% 25% 12% 1	760
	21st to end	Night	29% 15% 23% 24% 8% 1	836
November	1st to 10th	Night	30% 12% 24% 26% 7% 1	835
	11th to 20th	Night	29% 14% 26% 23% 6% 1	900
	21st to end	Night	30% 14% 26% 23% 6% 1	900
December	1st to 10th	Night	28% 12% 28% 24% 7% 1	900
	11th to 20th	Night	28% 19% 25% 21% 7%	900
	21st to end	Night	27% 16% 24% 24% 8% 2	990

Page generated at 2025-05-23 09:21:01. Version ac07

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