Mount Albert Lion's Club
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Mount Albert Lion's Club clear sky chart from 2005-11-06 to 2024-11-04.

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	15% 11% 4 9% 5% 5% 5% 4 5% 7% 32%	101759
	Night	14% 11% 4 9% 5% 5% 5% 4 5% 6% 32%	97237
Transparency	Day	50% 6% 12% 20% 10% 1	105361
	Night	49% 6% 13% 20% 10% 1	101723
Seeing	Day	19% 16% 31% 21% 10% 3	14648
	Night	19% 14% 32% 24% 9% 1	23761

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	15% 16% 5% 11% 5% 5% 5% 3 4 5% 25%	2517
	11th to 20th	Day	10% 16% 8% 17% 8% 7% 5% 3 4 5% 15%	2712
	21st to end	Day	19% 21% 7% 13% 6% 5% 4 3 4 4 14%	3124
February	1st to 10th	Day	14% 16% 5% 13% 8% 8% 5% 4 4 4 18%	1710
	11th to 20th	Day	11% 15% 7% 12% 7% 5% 5% 3 5% 6% 23%	1663
	21st to end	Day	16% 16% 5% 10% 6% 6% 4 4 4 6% 23%	1456
March	1st to 10th	Day	17% 12% 5% 9% 5% 4 4 3 4 5% 31%	3432
	11th to 20th	Day	10% 17% 6% 10% 6% 5% 5% 4 5% 5% 27%	3480
	21st to end	Day	15% 11% 4 10% 5% 4 4 3 4 5% 36%	3815
April	1st to 10th	Day	18% 14% 4 9% 4 5% 5% 3 5% 5% 28%	2251
	11th to 20th	Day	19% 12% 3 7% 4 4 3 4 6% 5% 35%	2326
	21st to end	Day	20% 11% 4 8% 4 3 3 3 5% 6% 33%	2470
May	1st to 10th	Day	17% 9% 3 8% 5% 4 4 4 6% 7% 33%	4128
	11th to 20th	Day	16% 10% 3 7% 5% 4 4 4 6% 7% 32%	4398
	21st to end	Day	12% 7% 2 6% 4 4 5% 4 5% 7% 44%	4837
June	1st to 10th	Day	17% 8% 3 6% 4 4 5% 4 7% 8% 35%	2660
	11th to 20th	Day	13% 6% 2 6% 5% 4 6% 4 6% 9% 38%	2660
	21st to end	Day	14% 7% 3 6% 5% 4 5% 4 5% 9% 37%	2838
July	1st to 10th	Day	11% 6% 2 7% 5% 5% 6% 5% 7% 10% 37%	4536
	11th to 20th	Day	10% 5% 2 6% 5% 5% 6% 4 7% 9% 41%	4440
	21st to end	Day	8% 6% 2 7% 6% 5% 6% 4 7% 8% 42%	4563
August	1st to 10th	Day	15% 9% 3 6% 4 4 5% 4 7% 8% 35%	4104
	11th to 20th	Day	13% 7% 3 8% 5% 4 5% 4 7% 10% 34%	4044
	21st to end	Day	10% 6% 2 6% 4 4 5% 4 6% 8% 44%	4352
September	1st to 10th	Day	14% 7% 2 6% 5% 5% 4 4 5% 8% 41%	2280
	11th to 20th	Day	12% 6% 2 6% 5% 4 5% 4 5% 8% 43%	2180
	21st to end	Day	13% 7% 3 9% 5% 4 4 4 5% 7% 37%	2043
October	1st to 10th	Day	18% 9% 3 8% 5% 5% 4 3 5% 6% 35%	1900
	11th to 20th	Day	20% 11% 4 8% 5% 5% 5% 3 5% 7% 27%	1900
	21st to end	Day	25% 14% 4 9% 5% 3 4 3 5% 5% 22%	2090
November	1st to 10th	Day	14% 14% 3 8% 5% 5% 5% 3 6% 6% 30%	1612
	11th to 20th	Day	13% 17% 4 10% 7% 5% 5% 5% 5% 5% 23%	1520
	21st to end	Day	18% 18% 5% 12% 5% 5% 5% 4 5% 6% 19%	1520
December	1st to 10th	Day	15% 18% 7% 16% 8% 5% 5% 3 5% 5% 12%	1520
	11th to 20th	Day	18% 15% 4 11% 8% 7% 5% 3 5% 7% 19%	1906
	21st to end	Day	25% 17% 7% 15% 5% 5% 4 3 4 3 12%	2772
January	1st to 10th	Night	15% 16% 6% 13% 7% 6% 5% 4 5% 5% 17%	4429
	11th to 20th	Night	11% 13% 6% 17% 10% 6% 6% 4 5% 5% 16%	4244
	21st to end	Night	18% 15% 7% 11% 7% 5% 5% 4 5% 5% 17%	4532
February	1st to 10th	Night	12% 17% 5% 12% 8% 6% 6% 4 5% 5% 21%	2470
	11th to 20th	Night	13% 15% 6% 11% 6% 7% 5% 4 5% 5% 24%	2403
	21st to end	Night	13% 13% 5% 12% 6% 6% 4 4 6% 6% 26%	1995
March	1st to 10th	Night	16% 12% 4 9% 5% 5% 4 3 5% 6% 31%	3408
	11th to 20th	Night	12% 13% 5% 9% 5% 4 4 4 5% 6% 33%	3479
	21st to end	Night	14% 8% 4 11% 5% 4 4 4 5% 6% 35%	3817
April	1st to 10th	Night	19% 13% 4 8% 5% 4 4 4 5% 6% 30%	1928
	11th to 20th	Night	17% 9% 3 7% 5% 4 4 4 4 6% 37%	1820
	21st to end	Night	16% 11% 4 7% 4 4 4 4 5% 8% 34%	1710
May	1st to 10th	Night	17% 8% 3 6% 4 4 4 4 6% 6% 39%	2811
	11th to 20th	Night	15% 8% 2 6% 4 4 5% 4 7% 7% 38%	2495
	21st to end	Night	11% 5% 2 5% 4 4 4 3 5% 8% 50%	2738
June	1st to 10th	Night	13% 6% 4 7% 5% 5% 5% 3 6% 7% 40%	1520
	11th to 20th	Night	11% 5% 2 6% 5% 4 5% 5% 7% 8% 42%	1519
	21st to end	Night	12% 7% 2 7% 5% 4 4 4 6% 7% 42%	1330
July	1st to 10th	Night	6% 5% 2 6% 5% 4 5% 4 6% 8% 49%	2417
	11th to 20th	Night	12% 5% 2 5% 3 3 4 4 5% 8% 49%	2520
	21st to end	Night	7% 6% 1 5% 4 4 4 5% 6% 9% 50%	2986
August	1st to 10th	Night	9% 6% 3 6% 4 4 4 4 6% 7% 48%	2825
	11th to 20th	Night	13% 6% 2 5% 4 3 3 3 6% 8% 48%	2785
	21st to end	Night	10% 6% 2 6% 4 4 5% 3 5% 8% 47%	3270
September	1st to 10th	Night	10% 6% 2 7% 4 5% 4 3 6% 7% 46%	1900
	11th to 20th	Night	11% 5% 2 5% 4 4 3 3 4 7% 51%	1997
	21st to end	Night	15% 7% 3 6% 4 4 5% 2 5% 7% 41%	2136
October	1st to 10th	Night	16% 6% 4 8% 5% 4 4 4 6% 6% 39%	2280
	11th to 20th	Night	17% 10% 3 8% 6% 5% 5% 4 5% 6% 31%	2280
	21st to end	Night	22% 11% 3 8% 5% 5% 5% 4 6% 6% 26%	2508
November	1st to 10th	Night	17% 12% 3 7% 4 4 4 3 6% 6% 33%	2533
	11th to 20th	Night	16% 15% 5% 9% 5% 5% 5% 3 6% 6% 25%	2660
	21st to end	Night	17% 15% 5% 10% 6% 4 5% 4 5% 6% 22%	2660
December	1st to 10th	Night	18% 17% 6% 12% 7% 5% 4 3 5% 6% 16%	2660
	11th to 20th	Night	14% 19% 6% 13% 6% 5% 5% 4 5% 5% 18%	3288
	21st to end	Night	25% 17% 6% 15% 6% 5% 4 3 4 5% 11%	4884

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	60% 5% 16% 12% 7%	2518
	11th to 20th	Day	70% 5% 11% 9% 4	2712
	21st to end	Day	72% 6% 9% 8% 4 1	3124
February	1st to 10th	Day	67% 6% 9% 14% 4 1	1710
	11th to 20th	Day	61% 7% 8% 16% 7% 1	1672
	21st to end	Day	62% 5% 9% 16% 7% 1	1456
March	1st to 10th	Day	55% 5% 13% 17% 10%	3435
	11th to 20th	Day	55% 7% 11% 17% 8% 1	3480
	21st to end	Day	48% 7% 10% 19% 15% 2	3815
April	1st to 10th	Day	57% 6% 9% 18% 10% 1	2251
	11th to 20th	Day	49% 6% 9% 20% 14% 1	2326
	21st to end	Day	52% 6% 10% 18% 12% 3	2470
May	1st to 10th	Day	46% 8% 12% 20% 13% 2	4140
	11th to 20th	Day	48% 8% 13% 20% 10% 1	4402
	21st to end	Day	37% 7% 14% 23% 17% 3	4837
June	1st to 10th	Day	45% 7% 13% 20% 15% 1	2660
	11th to 20th	Day	40% 7% 13% 23% 16% 1	2660
	21st to end	Day	44% 7% 13% 23% 13% 1	2838
July	1st to 10th	Day	42% 5% 15% 22% 14% 1	4466
	11th to 20th	Day	36% 7% 14% 33% 9% 1	4365
	21st to end	Day	38% 8% 13% 25% 15% 1	4417
August	1st to 10th	Day	44% 7% 14% 22% 12% 1	4091
	11th to 20th	Day	43% 7% 15% 26% 9%	4083
	21st to end	Day	36% 6% 13% 34% 11% 1	4352
September	1st to 10th	Day	40% 7% 14% 28% 10% 1	2280
	11th to 20th	Day	37% 7% 14% 28% 14%	2180
	21st to end	Day	46% 7% 13% 25% 9%	2043
October	1st to 10th	Day	43% 5% 13% 26% 12% 1	3160
	11th to 20th	Day	47% 4 14% 20% 14%	3140
	21st to end	Day	57% 5% 14% 18% 5%	3428
November	1st to 10th	Day	51% 7% 15% 18% 8% 1	1612
	11th to 20th	Day	60% 7% 12% 13% 8% 1	1520
	21st to end	Day	66% 6% 11% 14% 2	1520
December	1st to 10th	Day	72% 7% 10% 9% 2	1520
	11th to 20th	Day	64% 9% 12% 11% 5%	1906
	21st to end	Day	77% 4 9% 7% 2	2772
January	1st to 10th	Night	63% 8% 15% 10% 4	4429
	11th to 20th	Night	67% 7% 13% 10% 3 1	4244
	21st to end	Night	66% 6% 13% 10% 4 1	4532
February	1st to 10th	Night	63% 6% 10% 17% 4 1	2470
	11th to 20th	Night	58% 7% 10% 17% 7%	2405
	21st to end	Night	55% 7% 13% 17% 8%	1995
March	1st to 10th	Night	53% 6% 11% 21% 8% 1	3418
	11th to 20th	Night	47% 8% 14% 21% 9% 2	3480
	21st to end	Night	43% 10% 11% 21% 15% 2	3817
April	1st to 10th	Night	54% 4 9% 20% 12% 1	1928
	11th to 20th	Night	47% 5% 9% 21% 15% 2	1820
	21st to end	Night	49% 5% 11% 18% 15% 2	1710
May	1st to 10th	Night	43% 6% 13% 19% 16% 3	2818
	11th to 20th	Night	42% 8% 14% 23% 11% 2	2496
	21st to end	Night	31% 7% 14% 26% 19% 2	2739
June	1st to 10th	Night	42% 6% 11% 24% 16% 2	1520
	11th to 20th	Night	37% 6% 13% 21% 21% 2	1519
	21st to end	Night	39% 7% 14% 24% 15% 1	1330
July	1st to 10th	Night	32% 5% 16% 27% 19% 2	2377
	11th to 20th	Night	33% 4 14% 34% 14% 1	2472
	21st to end	Night	30% 8% 15% 32% 15% 1	2891
August	1st to 10th	Night	36% 5% 14% 29% 15% 2	2814
	11th to 20th	Night	34% 5% 18% 30% 12% 1	2812
	21st to end	Night	35% 6% 13% 33% 12% 1	3270
September	1st to 10th	Night	36% 6% 16% 27% 14% 1	1900
	11th to 20th	Night	31% 6% 12% 32% 18% 1	1997
	21st to end	Night	42% 6% 12% 27% 12%	2136
October	1st to 10th	Night	35% 5% 10% 28% 22% 1	3800
	11th to 20th	Night	47% 5% 15% 21% 12%	3779
	21st to end	Night	45% 7% 15% 25% 7%	4120
November	1st to 10th	Night	48% 6% 13% 22% 10% 1	2533
	11th to 20th	Night	56% 7% 13% 15% 8% 2	2660
	21st to end	Night	60% 8% 15% 13% 3	2660
December	1st to 10th	Night	68% 7% 11% 11% 3	2660
	11th to 20th	Night	66% 7% 10% 13% 3	3288
	21st to end	Night	76% 6% 9% 7% 2	4884

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	18% 26% 32% 18% 6% 1	180
	11th to 20th	Day	21% 28% 30% 15% 4 1	234
	21st to end	Day	23% 23% 37% 15% 2	297
February	1st to 10th	Day	22% 29% 34% 11% 3	270
	11th to 20th	Day	23% 24% 44% 8% 1	270
	21st to end	Day	34% 23% 34% 9%	244
March	1st to 10th	Day	23% 22% 36% 15% 4	460
	11th to 20th	Day	21% 24% 33% 18% 3 1	460
	21st to end	Day	29% 20% 29% 17% 4 1	506
April	1st to 10th	Day	26% 21% 33% 13% 7%	460
	11th to 20th	Day	32% 19% 24% 16% 6% 3	452
	21st to end	Day	25% 16% 34% 16% 8% 2	460
May	1st to 10th	Day	20% 15% 31% 20% 9% 4	463
	11th to 20th	Day	21% 13% 28% 25% 10% 3	487
	21st to end	Day	15% 13% 31% 24% 13% 4	529
June	1st to 10th	Day	17% 15% 29% 28% 9% 1	490
	11th to 20th	Day	15% 14% 29% 27% 13% 2	490
	21st to end	Day	18% 11% 34% 25% 10% 2	668
July	1st to 10th	Day	11% 8% 31% 29% 17% 4	542
	11th to 20th	Day	13% 8% 27% 29% 16% 7%	484
	21st to end	Day	9% 7% 34% 32% 13% 5%	532
August	1st to 10th	Day	13% 9% 26% 27% 16% 9%	486
	11th to 20th	Day	12% 9% 23% 27% 22% 8%	479
	21st to end	Day	14% 9% 30% 26% 15% 7%	539
September	1st to 10th	Day	13% 9% 28% 25% 16% 7%	490
	11th to 20th	Day	9% 9% 25% 23% 20% 13%	490
	21st to end	Day	14% 14% 31% 22% 13% 6%	490
October	1st to 10th	Day	23% 12% 29% 19% 13% 4	490
	11th to 20th	Day	23% 21% 32% 17% 7% 1	490
	21st to end	Day	30% 19% 32% 16% 4	539
November	1st to 10th	Day	23% 22% 31% 16% 7% 1	259
	11th to 20th	Day	22% 28% 29% 15% 4 2	180
	21st to end	Day	27% 21% 40% 11% 1	180
December	1st to 10th	Day	23% 23% 37% 13% 4	180
	11th to 20th	Day	27% 24% 33% 12% 3 1	180
	21st to end	Day	27% 22% 38% 11% 2	198
January	1st to 10th	Night	23% 22% 36% 14% 4 1	760
	11th to 20th	Night	25% 18% 33% 19% 4 1	760
	21st to end	Night	19% 15% 37% 22% 6%	836
February	1st to 10th	Night	20% 21% 38% 19% 1	760
	11th to 20th	Night	22% 18% 38% 19% 3	743
	21st to end	Night	21% 23% 37% 16% 3	628
March	1st to 10th	Night	19% 21% 37% 19% 3	760
	11th to 20th	Night	21% 21% 35% 18% 4 1	760
	21st to end	Night	19% 18% 34% 22% 6%	836
April	1st to 10th	Night	25% 16% 34% 21% 3	760
	11th to 20th	Night	20% 16% 35% 20% 8% 1	696
	21st to end	Night	22% 12% 32% 25% 8%	570
May	1st to 10th	Night	19% 9% 30% 30% 11% 1	561
	11th to 20th	Night	16% 6% 35% 30% 11% 1	374
	21st to end	Night	12% 8% 29% 35% 16% 1	411
June	1st to 10th	Night	14% 8% 34% 34% 10%	380
	11th to 20th	Night	12% 8% 34% 33% 13% 1	380
	21st to end	Night	16% 6% 29% 35% 13% 1	380
July	1st to 10th	Night	6% 7% 26% 41% 19% 1	370
	11th to 20th	Night	11% 6% 28% 35% 20% 1	368
	21st to end	Night	7% 6% 28% 39% 19% 1	562
August	1st to 10th	Night	11% 2 22% 36% 27% 1	567
	11th to 20th	Night	8% 5% 19% 39% 26% 3	564
	21st to end	Night	11% 6% 28% 33% 19% 2	708
September	1st to 10th	Night	12% 8% 27% 31% 18% 4	760
	11th to 20th	Night	13% 7% 24% 29% 22% 5%	760
	21st to end	Night	18% 10% 22% 31% 15% 4	760
October	1st to 10th	Night	19% 9% 31% 24% 15% 1	760
	11th to 20th	Night	21% 17% 32% 21% 9% 1	760
	21st to end	Night	27% 14% 34% 20% 4	836
November	1st to 10th	Night	24% 16% 31% 21% 8% 1	755
	11th to 20th	Night	22% 21% 31% 19% 6% 1	760
	21st to end	Night	24% 20% 30% 21% 4	760
December	1st to 10th	Night	27% 19% 36% 14% 3	760
	11th to 20th	Night	21% 22% 36% 16% 3 1	760
	21st to end	Night	29% 19% 35% 15% 2	836

Page generated at 2024-11-01 22:47:44. Version ac07

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