Pinhey's Point
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pinhey's Point clear sky chart from 2005-11-06 to 2024-11-05.

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	17% 9% 3 8% 5% 5% 4 4 6% 7% 33%	101604
	Night	17% 11% 4 8% 5% 5% 4 3 5% 6% 31%	97443
Transparency	Day	50% 5% 13% 22% 10% 1	105100
	Night	53% 5% 12% 20% 10% 1	102036
Seeing	Day	22% 16% 30% 20% 10% 3	14468
	Night	23% 12% 28% 26% 10% 1	23542

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	16% 16% 5% 12% 6% 5% 5% 4 5% 5% 20%	2517
	11th to 20th	Day	15% 12% 6% 15% 7% 6% 5% 3 5% 5% 22%	2520
	21st to end	Day	14% 18% 7% 12% 7% 7% 5% 4 5% 4 18%	2900
February	1st to 10th	Day	13% 16% 4 13% 7% 5% 4 4 5% 5% 24%	1710
	11th to 20th	Day	13% 14% 6% 10% 6% 5% 4 4 4 6% 28%	1663
	21st to end	Day	20% 13% 4 9% 6% 4 4 5% 6% 5% 26%	1566
March	1st to 10th	Day	21% 14% 4 7% 6% 5% 4 3 4 5% 26%	3134
	11th to 20th	Day	13% 15% 5% 11% 6% 5% 5% 3 4 6% 28%	3480
	21st to end	Day	14% 8% 2 6% 6% 4 4 3 5% 6% 41%	4024
April	1st to 10th	Day	22% 12% 3 6% 4 4 4 3 4 7% 32%	2280
	11th to 20th	Day	22% 9% 3 6% 5% 3 3 3 4 5% 36%	2254
	21st to end	Day	21% 10% 3 8% 5% 4 3 4 4 5% 31%	2419
May	1st to 10th	Day	21% 8% 3 8% 4 5% 5% 4 6% 7% 31%	4426
	11th to 20th	Day	17% 8% 3 8% 5% 5% 5% 4 5% 8% 33%	4398
	21st to end	Day	15% 7% 3 7% 5% 5% 4 4 5% 7% 37%	4837
June	1st to 10th	Day	21% 7% 3 8% 5% 5% 5% 4 5% 7% 30%	2660
	11th to 20th	Day	14% 5% 2 7% 5% 5% 4 5% 6% 8% 38%	2660
	21st to end	Day	19% 6% 3 6% 5% 5% 6% 5% 7% 8% 31%	2660
July	1st to 10th	Day	12% 7% 3 7% 5% 5% 5% 5% 8% 9% 35%	4440
	11th to 20th	Day	12% 6% 2 6% 5% 5% 5% 4 6% 8% 41%	4440
	21st to end	Day	11% 5% 2 6% 4 4 5% 4 6% 9% 44%	4814
August	1st to 10th	Day	14% 7% 3 8% 4 5% 5% 4 6% 8% 36%	4340
	11th to 20th	Day	16% 6% 2 6% 4 4 4 4 6% 9% 38%	4012
	21st to end	Day	13% 5% 2 5% 5% 4 5% 4 6% 9% 40%	4180
September	1st to 10th	Day	13% 5% 2 6% 4 4 5% 4 5% 8% 43%	2280
	11th to 20th	Day	12% 6% 2 6% 4 4 4 4 5% 8% 46%	2280
	21st to end	Day	17% 5% 3 6% 5% 4 4 3 6% 8% 39%	2025
October	1st to 10th	Day	20% 7% 3 6% 4 4 5% 3 6% 7% 35%	1900
	11th to 20th	Day	22% 8% 3 8% 4 5% 5% 3 5% 7% 29%	1900
	21st to end	Day	25% 9% 3 8% 4 4 5% 4 4 5% 28%	1943
November	1st to 10th	Day	16% 9% 2 8% 4 5% 6% 4 7% 6% 34%	1704
	11th to 20th	Day	21% 12% 3 8% 5% 5% 4 4 6% 5% 27%	1520
	21st to end	Day	22% 14% 4 10% 6% 6% 5% 4 4 6% 20%	1520
December	1st to 10th	Day	21% 18% 6% 10% 6% 5% 4 3 5% 6% 16%	1520
	11th to 20th	Day	21% 14% 4 10% 5% 4 5% 4 5% 5% 24%	1906
	21st to end	Day	28% 18% 6% 9% 5% 3 3 2 3 3 19%	2772
January	1st to 10th	Night	17% 18% 6% 12% 5% 5% 4 3 4 5% 20%	4429
	11th to 20th	Night	12% 14% 5% 13% 8% 6% 5% 4 4 5% 23%	4440
	21st to end	Night	16% 20% 6% 10% 6% 6% 4 3 4 4 21%	4752
February	1st to 10th	Night	14% 14% 4 13% 7% 5% 5% 3 5% 6% 24%	2470
	11th to 20th	Night	14% 13% 5% 11% 6% 5% 4 3 4 6% 29%	2403
	21st to end	Night	17% 13% 4 8% 6% 5% 5% 3 4 5% 29%	1886
March	1st to 10th	Night	21% 12% 3 9% 5% 4 4 3 3 5% 31%	3703
	11th to 20th	Night	16% 16% 5% 11% 6% 4 4 3 5% 5% 26%	3479
	21st to end	Night	16% 8% 3 7% 5% 4 3 3 5% 6% 40%	3608
April	1st to 10th	Night	20% 10% 3 8% 4 5% 4 3 6% 5% 33%	1900
	11th to 20th	Night	19% 9% 3 8% 5% 4 4 4 4 5% 35%	1875
	21st to end	Night	21% 9% 3 7% 5% 4 4 3 5% 5% 34%	1777
May	1st to 10th	Night	20% 9% 3 7% 5% 4 6% 5% 6% 7% 29%	2514
	11th to 20th	Night	19% 9% 3 6% 5% 4 5% 4 5% 7% 34%	2495
	21st to end	Night	15% 7% 3 6% 5% 4 4 5% 6% 6% 39%	2738
June	1st to 10th	Night	15% 7% 2 7% 5% 5% 5% 4 6% 9% 34%	1520
	11th to 20th	Night	14% 6% 2 7% 5% 4 3 4 6% 7% 43%	1520
	21st to end	Night	19% 8% 2 6% 4 4 5% 4 6% 7% 36%	1520
July	1st to 10th	Night	13% 7% 3 8% 6% 6% 6% 4 6% 7% 34%	2520
	11th to 20th	Night	13% 6% 3 7% 4 4 5% 4 5% 8% 41%	2520
	21st to end	Night	10% 6% 2 5% 6% 5% 5% 4 7% 7% 44%	2739
August	1st to 10th	Night	12% 8% 2 7% 4 5% 4 4 6% 9% 39%	2587
	11th to 20th	Night	15% 6% 3 6% 4 4 4 4 6% 7% 41%	2785
	21st to end	Night	13% 5% 2 6% 5% 4 5% 4 6% 8% 41%	3476
September	1st to 10th	Night	11% 6% 2 5% 5% 5% 4 4 5% 7% 47%	1900
	11th to 20th	Night	14% 4 2 6% 3 4 3 3 5% 6% 50%	1900
	21st to end	Night	18% 6% 2 6% 5% 4 3 2 5% 5% 44%	2150
October	1st to 10th	Night	18% 8% 3 6% 4 4 5% 4 5% 6% 39%	2280
	11th to 20th	Night	21% 8% 2 7% 6% 6% 5% 3 5% 6% 31%	2280
	21st to end	Night	23% 10% 3 8% 5% 5% 5% 3 5% 6% 28%	2655
November	1st to 10th	Night	20% 10% 3 7% 5% 4 3 3 5% 6% 33%	2470
	11th to 20th	Night	19% 11% 4 8% 5% 5% 5% 4 5% 5% 29%	2660
	21st to end	Night	22% 13% 4 9% 6% 5% 3 3 5% 7% 23%	2660
December	1st to 10th	Night	22% 17% 5% 10% 6% 4 5% 4 6% 5% 17%	2660
	11th to 20th	Night	22% 14% 4 9% 6% 4 4 3 4 4 26%	3288
	21st to end	Night	30% 18% 4 10% 4 3 4 3 3 4 18%	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	65% 4 14% 10% 6% 1	2518
	11th to 20th	Day	65% 3 12% 14% 6% 1	2520
	21st to end	Day	70% 4 10% 10% 5% 1	2900
February	1st to 10th	Day	62% 4 11% 18% 4 2	1710
	11th to 20th	Day	57% 3 12% 17% 9% 1	1672
	21st to end	Day	59% 4 11% 14% 10% 2	1566
March	1st to 10th	Day	61% 3 9% 17% 9% 1	3137
	11th to 20th	Day	58% 4 12% 16% 9% 2	3480
	21st to end	Day	43% 3 8% 26% 17% 3	4024
April	1st to 10th	Day	54% 3 8% 21% 12% 3	2280
	11th to 20th	Day	51% 3 6% 22% 15% 2	2254
	21st to end	Day	55% 4 8% 15% 14% 4	2419
May	1st to 10th	Day	51% 5% 9% 22% 10% 2	4440
	11th to 20th	Day	50% 5% 14% 20% 10% 2	4402
	21st to end	Day	45% 4 13% 21% 15% 2	4837
June	1st to 10th	Day	52% 5% 11% 20% 11% 1	2660
	11th to 20th	Day	41% 6% 13% 24% 13% 2	2660
	21st to end	Day	49% 6% 14% 21% 11%	2660
July	1st to 10th	Day	42% 6% 15% 25% 12%	4370
	11th to 20th	Day	38% 5% 15% 31% 10%	4365
	21st to end	Day	36% 6% 15% 32% 11%	4661
August	1st to 10th	Day	44% 6% 16% 24% 10%	4326
	11th to 20th	Day	42% 5% 15% 28% 9%	4051
	21st to end	Day	39% 5% 15% 28% 12% 1	4180
September	1st to 10th	Day	39% 6% 15% 28% 12%	2280
	11th to 20th	Day	36% 5% 14% 32% 13% 1	2280
	21st to end	Day	43% 6% 14% 27% 10%	2025
October	1st to 10th	Day	48% 5% 12% 29% 7%	3160
	11th to 20th	Day	46% 5% 15% 25% 8%	3140
	21st to end	Day	50% 5% 18% 20% 7%	3181
November	1st to 10th	Day	48% 6% 15% 24% 6% 1	1704
	11th to 20th	Day	57% 5% 14% 15% 8% 1	1520
	21st to end	Day	65% 6% 12% 9% 7% 1	1520
December	1st to 10th	Day	69% 5% 12% 11% 3 1	1520
	11th to 20th	Day	62% 5% 14% 14% 5%	1906
	21st to end	Day	72% 3 7% 15% 3	2772
January	1st to 10th	Night	67% 3 15% 11% 3	4429
	11th to 20th	Night	63% 5% 14% 13% 5%	4440
	21st to end	Night	69% 3 10% 11% 6% 1	4752
February	1st to 10th	Night	61% 4 10% 16% 7% 1	2470
	11th to 20th	Night	57% 4 11% 20% 8% 1	2405
	21st to end	Night	56% 4 10% 19% 11% 1	1886
March	1st to 10th	Night	57% 3 10% 19% 9% 2	3713
	11th to 20th	Night	60% 3 12% 16% 8% 1	3480
	21st to end	Night	44% 4 7% 23% 17% 4	3608
April	1st to 10th	Night	53% 4 9% 18% 14% 2	1900
	11th to 20th	Night	50% 4 7% 21% 16% 1	1875
	21st to end	Night	53% 4 7% 16% 16% 4	1777
May	1st to 10th	Night	52% 5% 11% 20% 9% 3	2520
	11th to 20th	Night	48% 5% 12% 22% 11% 2	2496
	21st to end	Night	43% 4 14% 20% 17% 2	2739
June	1st to 10th	Night	46% 6% 13% 24% 10% 1	1520
	11th to 20th	Night	39% 5% 12% 26% 16% 2	1520
	21st to end	Night	46% 6% 13% 21% 14% 1	1520
July	1st to 10th	Night	47% 6% 14% 20% 13% 1	2480
	11th to 20th	Night	40% 5% 13% 33% 9%	2472
	21st to end	Night	37% 6% 14% 27% 15%	2651
August	1st to 10th	Night	41% 7% 15% 25% 11%	2577
	11th to 20th	Night	41% 5% 16% 30% 8%	2812
	21st to end	Night	40% 6% 15% 26% 12% 2	3476
September	1st to 10th	Night	36% 6% 11% 31% 15% 1	1900
	11th to 20th	Night	35% 4 14% 35% 10% 1	1900
	21st to end	Night	42% 4 12% 31% 12%	2150
October	1st to 10th	Night	40% 5% 13% 30% 11%	3800
	11th to 20th	Night	47% 6% 14% 25% 9%	3779
	21st to end	Night	50% 6% 17% 19% 8%	4367
November	1st to 10th	Night	51% 4 14% 21% 9%	2470
	11th to 20th	Night	56% 4 11% 18% 9% 1	2660
	21st to end	Night	61% 6% 13% 15% 5%	2660
December	1st to 10th	Night	68% 5% 10% 13% 3	2660
	11th to 20th	Night	62% 4 10% 17% 7% 1	3288
	21st to end	Night	73% 3 7% 13% 4	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	23% 23% 33% 17% 5%	180
	11th to 20th	Day	27% 20% 34% 15% 4	180
	21st to end	Day	20% 17% 38% 21% 4	234
February	1st to 10th	Day	29% 24% 33% 11% 3	270
	11th to 20th	Day	27% 30% 35% 7% 1	270
	21st to end	Day	30% 24% 29% 15% 2	378
March	1st to 10th	Day	28% 18% 32% 17% 4	460
	11th to 20th	Day	25% 21% 34% 15% 3 1	460
	21st to end	Day	30% 20% 28% 15% 6% 1	506
April	1st to 10th	Day	31% 20% 28% 15% 6% 1	460
	11th to 20th	Day	32% 18% 24% 13% 10% 2	452
	21st to end	Day	30% 21% 29% 13% 7% 1	460
May	1st to 10th	Day	25% 15% 31% 19% 7% 3	463
	11th to 20th	Day	18% 19% 30% 21% 9% 3	487
	21st to end	Day	18% 16% 30% 23% 11% 1	529
June	1st to 10th	Day	25% 11% 30% 23% 8% 2	490
	11th to 20th	Day	15% 16% 30% 24% 12% 3	490
	21st to end	Day	21% 14% 31% 21% 11% 3	490
July	1st to 10th	Day	12% 8% 27% 35% 15% 4	485
	11th to 20th	Day	13% 7% 33% 28% 14% 4	484
	21st to end	Day	14% 8% 29% 32% 14% 4	532
August	1st to 10th	Day	13% 7% 28% 30% 17% 4	486
	11th to 20th	Day	13% 8% 25% 30% 17% 8%	479
	21st to end	Day	15% 11% 28% 25% 14% 7%	539
September	1st to 10th	Day	16% 10% 29% 21% 15% 8%	490
	11th to 20th	Day	12% 9% 25% 23% 20% 12%	490
	21st to end	Day	18% 11% 30% 21% 15% 5%	490
October	1st to 10th	Day	24% 14% 25% 20% 13% 4	490
	11th to 20th	Day	25% 19% 29% 18% 8% 1	490
	21st to end	Day	30% 18% 26% 21% 6%	462
November	1st to 10th	Day	25% 18% 29% 19% 8% 1	374
	11th to 20th	Day	29% 22% 33% 11% 4 1	180
	21st to end	Day	28% 19% 36% 11% 4 1	180
December	1st to 10th	Day	31% 16% 38% 13% 3	180
	11th to 20th	Day	29% 27% 32% 9% 2	180
	21st to end	Day	28% 23% 34% 12% 2 1	198
January	1st to 10th	Night	28% 14% 34% 20% 4	760
	11th to 20th	Night	28% 18% 26% 22% 6% 1	760
	21st to end	Night	20% 12% 37% 26% 5%	836
February	1st to 10th	Night	22% 17% 35% 23% 4	760
	11th to 20th	Night	21% 17% 38% 19% 4	743
	21st to end	Night	25% 18% 28% 25% 4	628
March	1st to 10th	Night	24% 15% 34% 23% 3	760
	11th to 20th	Night	24% 18% 31% 21% 6%	760
	21st to end	Night	24% 16% 28% 25% 6%	836
April	1st to 10th	Night	27% 13% 30% 25% 5%	760
	11th to 20th	Night	25% 17% 29% 22% 7%	751
	21st to end	Night	26% 13% 29% 24% 8%	637
May	1st to 10th	Night	23% 8% 28% 31% 9% 2	380
	11th to 20th	Night	22% 9% 28% 31% 9%	374
	21st to end	Night	15% 7% 36% 29% 12%	411
June	1st to 10th	Night	19% 4 32% 34% 11%	380
	11th to 20th	Night	16% 8% 24% 36% 14% 2	380
	21st to end	Night	23% 5% 26% 31% 14% 1	380
July	1st to 10th	Night	11% 4 27% 39% 18%	370
	11th to 20th	Night	12% 5% 24% 44% 15% 1	368
	21st to end	Night	9% 5% 23% 45% 16% 1	416
August	1st to 10th	Night	12% 3 20% 41% 23%	420
	11th to 20th	Night	12% 4 18% 38% 24% 3	564
	21st to end	Night	13% 6% 24% 36% 19% 2	836
September	1st to 10th	Night	13% 6% 29% 31% 19% 2	760
	11th to 20th	Night	16% 6% 20% 31% 22% 4	760
	21st to end	Night	21% 7% 23% 27% 20% 2	760
October	1st to 10th	Night	23% 10% 24% 27% 15% 1	760
	11th to 20th	Night	26% 13% 27% 25% 8% 1	760
	21st to end	Night	26% 15% 28% 25% 6%	836
November	1st to 10th	Night	26% 13% 26% 26% 8% 1	760
	11th to 20th	Night	24% 16% 32% 18% 9% 1	760
	21st to end	Night	30% 15% 27% 22% 6%	760
December	1st to 10th	Night	30% 15% 29% 22% 3	760
	11th to 20th	Night	28% 16% 29% 21% 5% 1	760
	21st to end	Night	34% 16% 29% 17% 4	836

Page generated at 2024-11-03 02:11:30. Version ac07

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