Newman Vista Point
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Newman Vista Point clear sky chart from 2005-11-06 to 2025-04-26.

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	5% 3 1 3 2 2 3 2 4 5% 69%	117599
	Night	6% 3 1 3 2 2 3 2 4 5% 67%	119883
Transparency	Day	18% 5% 9% 19% 25% 25%	117352
	Night	20% 6% 10% 19% 24% 22%	119719
Seeing	Day	5% 6% 17% 30% 30% 12%	15913
	Night	6% 4 16% 39% 30% 5%	25446

By Month

Percentage Cloud Cover SW (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	9% 7% 2 6% 4 4 4 3 4 7% 50%	3713
	11th to 20th	Day	7% 6% 3 7% 4 4 4 3 3 5% 55%	4100
	21st to end	Day	13% 6% 2 6% 4 4 4 3 4 6% 46%	4510
February	1st to 10th	Day	12% 6% 2 6% 3 3 4 4 5% 7% 49%	1800
	11th to 20th	Day	8% 5% 2 5% 4 4 4 3 5% 8% 52%	1923
	21st to end	Day	11% 4 2 5% 4 4 4 3 5% 5% 54%	1650
March	1st to 10th	Day	8% 5% 2 6% 5% 5% 6% 4 8% 9% 43%	4692
	11th to 20th	Day	8% 4 1 4 3 4 4 3 5% 7% 56%	5000
	21st to end	Day	8% 5% 2 6% 4 4 4 4 6% 9% 48%	5694
April	1st to 10th	Day	7% 6% 2 5% 4 3 3 3 5% 6% 56%	2400
	11th to 20th	Day	5% 3 1 4 3 3 3 3 5% 6% 63%	2369
	21st to end	Day	4 3 1 3 2 2 3 2 4 6% 70%	2342
May	1st to 10th	Day	4 1 1 2 1 1 2 2 3 5% 78%	3800
	11th to 20th	Day	1 1 1 1 1 1 2 2 2 4 84%	4237
	21st to end	Day	1 1 1 1 1 1 2 3 3 84%	4813
June	1st to 10th	Day	1 2 1 2 2 2 3 2 4 6% 75%	2660
	11th to 20th	Day	1 1 1 1 1 1 2 3 88%	2660
	21st to end	Day	1 1 1 1 1 1 1 2 2 88%	2660
July	1st to 10th	Day	1 1 1 1 95%	4420
	11th to 20th	Day	1 1 1 1 1 1 2 1 2 2 86%	4276
	21st to end	Day	1 1 1 1 2 92%	4455
August	1st to 10th	Day	1 1 1 1 2 2 1 3 4 84%	4072
	11th to 20th	Day	1 1 1 2 93%	3724
	21st to end	Day	1 1 1 1 1 1 2 2 90%	4180
September	1st to 10th	Day	1 1 1 1 1 1 1 1 2 91%	2280
	11th to 20th	Day	1 1 1 1 1 1 1 1 3 5% 83%	2280
	21st to end	Day	1 1 2 1 1 2 1 2 4 84%	2058
October	1st to 10th	Day	1 1 1 2 2 1 2 2 3 5% 80%	3180
	11th to 20th	Day	2 1 2 2 2 1 2 3 4 82%	3161
	21st to end	Day	3 2 1 4 3 3 3 2 4 6% 70%	3448
November	1st to 10th	Day	5% 3 1 3 3 5% 4 3 5% 7% 62%	1850
	11th to 20th	Day	7% 4 1 4 2 3 5% 3 6% 7% 59%	1800
	21st to end	Day	8% 5% 1 5% 3 3 3 4 6% 7% 56%	1740
December	1st to 10th	Day	6% 4 2 5% 4 3 4 3 5% 8% 55%	2620
	11th to 20th	Day	15% 7% 4 8% 6% 5% 5% 4 6% 7% 33%	3028
	21st to end	Day	11% 7% 3 8% 5% 5% 6% 4 6% 8% 36%	4004
January	1st to 10th	Night	8% 5% 2 4 3 3 3 3 5% 7% 58%	6218
	11th to 20th	Night	10% 5% 2 5% 2 3 3 2 4 6% 58%	5880
	21st to end	Night	11% 6% 2 5% 3 3 4 3 4 6% 53%	6468
February	1st to 10th	Night	12% 5% 2 5% 3 3 3 3 4 6% 54%	2600
	11th to 20th	Night	8% 4 1 4 3 3 4 3 5% 9% 56%	2363
	21st to end	Night	10% 4 1 5% 3 3 3 2 3 6% 59%	1980
March	1st to 10th	Night	8% 5% 2 6% 4 5% 6% 4 6% 7% 47%	5187
	11th to 20th	Night	7% 4 2 6% 4 3 4 3 4 5% 58%	5000
	21st to end	Night	10% 5% 2 4 3 3 4 4 5% 8% 52%	5280
April	1st to 10th	Night	7% 4 1 4 4 3 4 3 5% 8% 58%	2000
	11th to 20th	Night	4 3 1 4 3 3 2 3 5% 6% 65%	1979
	21st to end	Night	3 2 1 2 2 2 2 3 4 7% 73%	1954
May	1st to 10th	Night	1 1 1 2 1 2 2 1 2 4 82%	3180
	11th to 20th	Night	2 1 1 1 1 2 1 2 4 87%	2641
	21st to end	Night	1 1 1 1 1 1 1 2 3 88%	2762
June	1st to 10th	Night	2 2 1 2 2 2 2 2 3 5% 78%	1520
	11th to 20th	Night	1 1 1 1 1 1 2 3 89%	1520
	21st to end	Night	1 1 1 1 2 92%	1520
July	1st to 10th	Night	1 1 1 1 1 2 95%	2540
	11th to 20th	Night	1 1 1 1 1 1 2 1 2 3 87%	2685
	21st to end	Night	1 1 1 1 1 1 1 2 3 89%	3109
August	1st to 10th	Night	1 1 1 1 1 2 2 3 3 85%	2866
	11th to 20th	Night	1 1 1 1 1 2 92%	3126
	21st to end	Night	1 1 1 1 1 1 1 1 92%	3498
September	1st to 10th	Night	1 1 1 2 2 92%	1900
	11th to 20th	Night	2 1 1 1 1 1 1 1 2 3 87%	1900
	21st to end	Night	1 1 1 1 2 1 1 1 2 3 86%	2118
October	1st to 10th	Night	2 1 1 1 2 2 1 3 4 83%	3800
	11th to 20th	Night	1 1 1 2 2 1 2 1 3 5% 82%	3777
	21st to end	Night	4 2 1 3 2 2 2 2 4 5% 74%	4121
November	1st to 10th	Night	5% 2 1 2 2 2 3 2 5% 6% 69%	2448
	11th to 20th	Night	6% 3 1 4 3 2 3 3 4 8% 63%	2600
	21st to end	Night	6% 4 1 4 3 3 4 3 4 6% 62%	2655
December	1st to 10th	Night	6% 3 1 3 3 3 4 3 5% 6% 62%	4560
	11th to 20th	Night	13% 6% 2 6% 5% 4 5% 4 7% 10% 37%	5176
	21st to end	Night	15% 7% 2 7% 5% 5% 5% 5% 6% 7% 36%	6952

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	30% 10% 21% 21% 14% 4	3713
	11th to 20th	Day	32% 8% 9% 13% 25% 13%	4100
	21st to end	Day	38% 8% 10% 14% 23% 8%	4510
February	1st to 10th	Day	35% 7% 10% 22% 18% 7%	1800
	11th to 20th	Day	29% 8% 15% 22% 21% 5%	1933
	21st to end	Day	32% 5% 13% 25% 19% 6%	1650
March	1st to 10th	Day	33% 12% 13% 18% 22% 2	4692
	11th to 20th	Day	26% 7% 13% 32% 14% 8%	5000
	21st to end	Day	28% 12% 17% 29% 12% 2	5694
April	1st to 10th	Day	28% 8% 13% 24% 20% 7%	2400
	11th to 20th	Day	21% 6% 13% 27% 25% 7%	2372
	21st to end	Day	17% 5% 12% 31% 29% 7%	2342
May	1st to 10th	Day	11% 4 9% 28% 28% 21%	3800
	11th to 20th	Day	7% 2 6% 27% 41% 17%	4240
	21st to end	Day	7% 3 10% 27% 40% 13%	4814
June	1st to 10th	Day	11% 5% 11% 23% 31% 18%	2660
	11th to 20th	Day	5% 2 6% 20% 37% 31%	2660
	21st to end	Day	6% 2 3 9% 30% 50%	2660
July	1st to 10th	Day	2 1 1 4 13% 79%	4351
	11th to 20th	Day	7% 2 3 5% 13% 70%	4201
	21st to end	Day	3 1 2 5% 27% 63%	4315
August	1st to 10th	Day	7% 2 2 6% 29% 54%	4057
	11th to 20th	Day	2 1 2 7% 30% 58%	3760
	21st to end	Day	4 1 3 9% 29% 54%	4179
September	1st to 10th	Day	4 2 3 8% 27% 56%	2280
	11th to 20th	Day	6% 2 6% 19% 41% 25%	2280
	21st to end	Day	7% 2 4 19% 39% 29%	2058
October	1st to 10th	Day	9% 2 5% 12% 22% 50%	3180
	11th to 20th	Day	8% 3 6% 22% 39% 21%	3161
	21st to end	Day	16% 4 6% 20% 36% 18%	3448
November	1st to 10th	Day	22% 7% 11% 23% 27% 10%	1850
	11th to 20th	Day	22% 9% 14% 28% 22% 4	1800
	21st to end	Day	27% 8% 11% 23% 25% 7%	1740
December	1st to 10th	Day	27% 5% 10% 31% 22% 5%	2620
	11th to 20th	Day	45% 9% 12% 20% 12% 2	3028
	21st to end	Day	42% 13% 17% 16% 10% 1	4004
January	1st to 10th	Night	24% 9% 21% 29% 14% 4	6218
	11th to 20th	Night	30% 7% 10% 15% 28% 9%	5880
	21st to end	Night	33% 8% 10% 14% 23% 12%	6468
February	1st to 10th	Night	32% 5% 10% 23% 21% 10%	2600
	11th to 20th	Night	25% 7% 14% 23% 24% 8%	2364
	21st to end	Night	26% 6% 11% 28% 19% 8%	1980
March	1st to 10th	Night	33% 11% 13% 15% 23% 4	5187
	11th to 20th	Night	27% 7% 15% 27% 16% 9%	5000
	21st to end	Night	27% 11% 19% 26% 14% 4	5280
April	1st to 10th	Night	24% 8% 14% 24% 22% 8%	2000
	11th to 20th	Night	20% 6% 14% 28% 22% 11%	1979
	21st to end	Night	13% 6% 13% 30% 30% 9%	1954
May	1st to 10th	Night	8% 4 10% 28% 29% 22%	3180
	11th to 20th	Night	6% 2 6% 20% 42% 24%	2641
	21st to end	Night	5% 2 8% 29% 42% 13%	2762
June	1st to 10th	Night	11% 5% 11% 20% 33% 20%	1520
	11th to 20th	Night	4 3 7% 17% 32% 36%	1520
	21st to end	Night	3 2 3 10% 31% 51%	1520
July	1st to 10th	Night	2 1 1 4 13% 80%	2500
	11th to 20th	Night	6% 2 3 4 17% 68%	2637
	21st to end	Night	4 1 2 8% 22% 62%	3011
August	1st to 10th	Night	7% 1 2 9% 30% 51%	2857
	11th to 20th	Night	3 1 1 6% 29% 60%	3156
	21st to end	Night	5% 1 3 9% 28% 55%	3498
September	1st to 10th	Night	4 2 3 8% 25% 59%	1900
	11th to 20th	Night	7% 1 5% 19% 36% 31%	1900
	21st to end	Night	7% 2 4 16% 36% 34%	2118
October	1st to 10th	Night	8% 3 5% 11% 17% 56%	3800
	11th to 20th	Night	9% 3 6% 25% 32% 25%	3777
	21st to end	Night	13% 3 5% 19% 37% 23%	4121
November	1st to 10th	Night	16% 6% 12% 24% 27% 16%	2448
	11th to 20th	Night	21% 5% 13% 24% 30% 7%	2600
	21st to end	Night	24% 6% 10% 23% 25% 11%	2655
December	1st to 10th	Night	23% 6% 8% 29% 26% 8%	4560
	11th to 20th	Night	38% 10% 16% 20% 14% 2	5176
	21st to end	Night	44% 12% 15% 19% 8% 3	6952

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% 9% 20% 28% 15% 5%	235
	11th to 20th	Day	10% 7% 23% 26% 25% 9%	400
	21st to end	Day	10% 6% 20% 29% 26% 9%	440
February	1st to 10th	Day	16% 11% 21% 20% 21% 11%	400
	11th to 20th	Day	10% 12% 27% 28% 17% 7%	482
	21st to end	Day	10% 11% 23% 34% 18% 4	414
March	1st to 10th	Day	12% 14% 20% 33% 17% 4	500
	11th to 20th	Day	12% 14% 21% 28% 18% 7%	500
	21st to end	Day	11% 13% 26% 30% 16% 5%	550
April	1st to 10th	Day	11% 10% 25% 26% 21% 7%	500
	11th to 20th	Day	6% 12% 24% 30% 21% 7%	492
	21st to end	Day	3 9% 26% 33% 20% 10%	481
May	1st to 10th	Day	4 8% 27% 34% 21% 6%	463
	11th to 20th	Day	3 7% 24% 31% 26% 9%	488
	21st to end	Day	3 8% 18% 32% 29% 11%	529
June	1st to 10th	Day	2 6% 19% 36% 28% 10%	490
	11th to 20th	Day	1 5% 19% 38% 28% 9%	490
	21st to end	Day	1 3 14% 32% 34% 15%	490
July	1st to 10th	Day	7% 33% 44% 16%	486
	11th to 20th	Day	1 4 32% 45% 18%	484
	21st to end	Day	1 5% 31% 43% 20%	531
August	1st to 10th	Day	2 1 9% 34% 38% 16%	487
	11th to 20th	Day	9% 31% 41% 18%	477
	21st to end	Day	1 6% 29% 45% 19%	539
September	1st to 10th	Day	1 2 8% 28% 43% 18%	490
	11th to 20th	Day	2 3 12% 33% 37% 13%	490
	21st to end	Day	1 3 11% 26% 41% 18%	490
October	1st to 10th	Day	2 5% 18% 21% 34% 20%	490
	11th to 20th	Day	3 5% 15% 25% 31% 20%	490
	21st to end	Day	4 4 15% 28% 32% 16%	539
November	1st to 10th	Day	5% 8% 16% 22% 33% 16%	386
	11th to 20th	Day	6% 5% 17% 27% 34% 11%	300
	21st to end	Day	8% 3 18% 30% 36% 5%	270
December	1st to 10th	Day	12% 8% 18% 27% 24% 13%	200
	11th to 20th	Day	11% 9% 19% 29% 24% 10%	200
	21st to end	Day	10% 12% 23% 29% 21% 4	220
January	1st to 10th	Night	14% 5% 17% 35% 23% 7%	800
	11th to 20th	Night	11% 5% 14% 37% 27% 7%	800
	21st to end	Night	13% 3 15% 36% 28% 5%	880
February	1st to 10th	Night	14% 8% 15% 33% 24% 6%	800
	11th to 20th	Night	9% 7% 18% 36% 25% 5%	784
	21st to end	Night	10% 6% 20% 43% 18% 3	660
March	1st to 10th	Night	11% 7% 21% 36% 21% 3	800
	11th to 20th	Night	9% 7% 23% 33% 24% 4	800
	21st to end	Night	9% 6% 25% 38% 20% 2	880
April	1st to 10th	Night	8% 6% 25% 39% 21% 2	800
	11th to 20th	Night	5% 8% 25% 37% 21% 4	791
	21st to end	Night	3 5% 27% 36% 24% 4	782
May	1st to 10th	Night	2 3 30% 40% 21% 3	760
	11th to 20th	Night	4 2 21% 42% 29% 2	460
	21st to end	Night	1 5% 21% 46% 26%	411
June	1st to 10th	Night	2 1 20% 53% 23% 1	380
	11th to 20th	Night	1 2 19% 51% 26% 1	380
	21st to end	Night	1 11% 53% 34% 1	380
July	1st to 10th	Night	8% 50% 41% 2	370
	11th to 20th	Night	3 45% 48% 3	448
	21st to end	Night	1 5% 40% 47% 6%	624
August	1st to 10th	Night	1 7% 44% 42% 5%	572
	11th to 20th	Night	10% 49% 37% 4	752
	21st to end	Night	1 6% 42% 46% 5%	836
September	1st to 10th	Night	1 7% 44% 41% 6%	760
	11th to 20th	Night	3 1 13% 42% 36% 5%	760
	21st to end	Night	2 1 11% 36% 42% 8%	760
October	1st to 10th	Night	3 3 12% 39% 34% 9%	760
	11th to 20th	Night	2 3 13% 35% 36% 10%	760
	21st to end	Night	4 3 13% 34% 31% 15%	836
November	1st to 10th	Night	4 3 16% 33% 35% 9%	780
	11th to 20th	Night	6% 2 15% 37% 33% 7%	800
	21st to end	Night	7% 4 17% 37% 29% 7%	800
December	1st to 10th	Night	11% 4 15% 38% 26% 7%	800
	11th to 20th	Night	13% 5% 17% 36% 26% 4	800
	21st to end	Night	13% 8% 20% 36% 20% 3	880

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