Springdale
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Springdale clear sky chart from 2005-11-06 to 2024-02-15.

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	21% 13% 5% 8% 6% 4 5% 4 5% 6% 24%	77864
	Night	20% 11% 5% 8% 6% 4 5% 5% 5% 6% 25%	81256
Transparency	Day	62% 6% 10% 15% 7% 1	77555
	Night	61% 6% 11% 15% 7% 1	81100
Seeing	Day	29% 17% 28% 18% 7% 2	16991
	Night	28% 15% 30% 20% 6% 1	24030

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	12% 12% 7% 13% 7% 4 5% 6% 5% 5% 24%	2259
	11th to 20th	Day	17% 13% 5% 12% 9% 5% 8% 5% 4 5% 16%	2530
	21st to end	Day	9% 13% 7% 9% 8% 5% 6% 5% 4 6% 29%	2783
February	1st to 10th	Day	16% 12% 4 11% 10% 5% 6% 5% 6% 6% 19%	1520
	11th to 20th	Day	17% 18% 6% 9% 7% 5% 5% 5% 5% 4 20%	1641
	21st to end	Day	12% 14% 6% 10% 8% 4 7% 5% 5% 6% 24%	1480
March	1st to 10th	Day	17% 17% 6% 9% 7% 4 5% 4 4 4 23%	1796
	11th to 20th	Day	17% 15% 6% 11% 7% 4 5% 5% 4 5% 21%	1886
	21st to end	Day	20% 18% 7% 9% 7% 4 4 3 3 4 21%	2310
April	1st to 10th	Day	22% 17% 7% 9% 8% 3 5% 4 4 5% 17%	2160
	11th to 20th	Day	19% 17% 6% 8% 5% 3 4 4 5% 5% 25%	2266
	21st to end	Day	25% 17% 6% 6% 6% 3 4 4 3 5% 22%	2340
May	1st to 10th	Day	26% 17% 4 8% 5% 3 3 3 4 4 22%	2482
	11th to 20th	Day	23% 14% 5% 6% 6% 3 3 4 4 5% 27%	2513
	21st to end	Day	25% 14% 4 6% 6% 3 4 5% 5% 6% 21%	2918
June	1st to 10th	Day	32% 11% 4 6% 6% 3 6% 4 4 6% 18%	2700
	11th to 20th	Day	28% 11% 3 5% 6% 3 5% 4 4 6% 24%	2700
	21st to end	Day	25% 9% 4 7% 6% 3 5% 5% 5% 6% 25%	2700
July	1st to 10th	Day	22% 9% 3 6% 6% 4 5% 5% 6% 7% 26%	2700
	11th to 20th	Day	18% 8% 3 6% 6% 4 6% 5% 6% 7% 30%	2623
	21st to end	Day	22% 9% 3 6% 6% 4 5% 6% 5% 7% 26%	2745
August	1st to 10th	Day	23% 8% 4 6% 6% 3 5% 5% 5% 7% 28%	2506
	11th to 20th	Day	23% 8% 3 7% 6% 3 4 5% 5% 7% 28%	2357
	21st to end	Day	19% 8% 3 7% 6% 3 5% 5% 6% 7% 30%	2534
September	1st to 10th	Day	24% 7% 3 6% 5% 3 5% 4 4 6% 33%	2160
	11th to 20th	Day	26% 9% 4 6% 6% 3 4 4 5% 6% 26%	2011
	21st to end	Day	18% 10% 4 7% 6% 3 5% 5% 5% 8% 29%	1980
October	1st to 10th	Day	21% 9% 3 7% 5% 3 4 5% 4 6% 33%	1948
	11th to 20th	Day	23% 14% 3 7% 6% 3 5% 4 4 7% 23%	1620
	21st to end	Day	23% 14% 3 8% 7% 3 4 4 4 6% 22%	1782
November	1st to 10th	Day	25% 14% 4 7% 6% 4 4 6% 5% 6% 18%	1670
	11th to 20th	Day	19% 15% 6% 7% 7% 3 4 3 5% 6% 25%	1474
	21st to end	Day	22% 15% 5% 9% 6% 3 5% 4 4 5% 21%	1330
December	1st to 10th	Day	21% 17% 7% 10% 7% 4 6% 5% 5% 4 15%	1330
	11th to 20th	Day	29% 13% 6% 8% 7% 3 4 4 5% 4 17%	1668
	21st to end	Day	21% 16% 6% 11% 6% 3 4 4 5% 5% 18%	2442
January	1st to 10th	Night	11% 11% 7% 10% 9% 4 5% 5% 6% 7% 26%	4694
	11th to 20th	Night	13% 11% 5% 12% 8% 5% 7% 6% 5% 7% 22%	4440
	21st to end	Night	10% 11% 6% 10% 8% 4 7% 8% 6% 7% 24%	4884
February	1st to 10th	Night	16% 11% 4 11% 9% 5% 7% 5% 5% 7% 20%	2660
	11th to 20th	Night	15% 16% 5% 9% 7% 4 6% 5% 5% 6% 22%	2295
	21st to end	Night	11% 13% 5% 8% 7% 4 6% 6% 5% 6% 30%	1776
March	1st to 10th	Night	19% 13% 5% 8% 6% 4 5% 4 5% 5% 25%	2151
	11th to 20th	Night	13% 13% 6% 9% 7% 4 6% 6% 6% 6% 23%	2072
	21st to end	Night	19% 15% 5% 9% 6% 3 4 4 4 5% 25%	2044
April	1st to 10th	Night	23% 15% 5% 8% 5% 3 4 4 4 5% 23%	1800
	11th to 20th	Night	20% 15% 5% 7% 5% 2 4 4 4 6% 27%	1644
	21st to end	Night	25% 16% 5% 5% 5% 2 4 4 3 6% 26%	1620
May	1st to 10th	Night	26% 12% 4 7% 6% 2 4 4 4 6% 23%	1476
	11th to 20th	Night	27% 11% 3 6% 5% 4 4 3 4 5% 29%	1381
	21st to end	Night	26% 12% 3 6% 5% 3 4 4 3 6% 27%	1356
June	1st to 10th	Night	32% 11% 3 7% 7% 4 3 4 5% 7% 18%	1260
	11th to 20th	Night	26% 9% 3 4 6% 3 4 5% 4 7% 28%	1260
	21st to end	Night	27% 9% 3 7% 5% 3 5% 4 4 6% 26%	1260
July	1st to 10th	Night	23% 7% 3 5% 5% 2 5% 5% 6% 7% 31%	1260
	11th to 20th	Night	18% 8% 3 4 6% 3 4 5% 6% 7% 36%	1334
	21st to end	Night	24% 8% 3 7% 5% 4 5% 4 4 6% 31%	1573
August	1st to 10th	Night	20% 8% 4 6% 7% 4 5% 5% 5% 7% 28%	1433
	11th to 20th	Night	23% 7% 3 6% 5% 3 4 4 6% 8% 32%	1543
	21st to end	Night	20% 6% 3 5% 5% 3 4 4 6% 9% 34%	1819
September	1st to 10th	Night	22% 8% 2 4 4 3 3 4 5% 7% 39%	1800
	11th to 20th	Night	25% 9% 3 4 6% 3 4 3 5% 5% 33%	1948
	21st to end	Night	21% 8% 3 5% 5% 3 5% 5% 6% 6% 34%	1980
October	1st to 10th	Night	21% 9% 4 6% 6% 3 4 4 5% 6% 31%	2009
	11th to 20th	Night	22% 11% 3 6% 5% 3 5% 5% 6% 5% 29%	2340
	21st to end	Night	26% 11% 3 6% 5% 3 5% 4 5% 6% 27%	2574
November	1st to 10th	Night	22% 12% 5% 7% 7% 4 5% 6% 6% 6% 22%	2408
	11th to 20th	Night	22% 11% 5% 8% 6% 4 5% 5% 5% 6% 21%	2706
	21st to end	Night	20% 15% 5% 10% 6% 4 5% 4 5% 6% 20%	2850
December	1st to 10th	Night	18% 16% 6% 10% 7% 5% 6% 6% 5% 6% 16%	2850
	11th to 20th	Night	29% 11% 6% 9% 7% 3 5% 5% 5% 6% 15%	3531
	21st to end	Night	21% 12% 6% 12% 6% 3 4 5% 5% 5% 19%	5225

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% 5% 9% 15% 7% 2	2260
	11th to 20th	Day	69% 8% 8% 10% 5%	2530
	21st to end	Day	57% 6% 10% 15% 8% 4	2783
February	1st to 10th	Day	64% 6% 11% 11% 6% 1	1520
	11th to 20th	Day	69% 5% 8% 10% 6% 1	1648
	21st to end	Day	63% 5% 7% 13% 11% 1	1480
March	1st to 10th	Day	66% 5% 8% 12% 8% 2	1800
	11th to 20th	Day	67% 6% 7% 12% 8%	1886
	21st to end	Day	70% 5% 5% 10% 8% 2	2310
April	1st to 10th	Day	71% 5% 8% 9% 5% 1	2160
	11th to 20th	Day	63% 5% 7% 14% 10% 1	2266
	21st to end	Day	66% 5% 7% 13% 8%	2340
May	1st to 10th	Day	68% 4 9% 13% 6%	2482
	11th to 20th	Day	63% 4 9% 15% 9% 1	2517
	21st to end	Day	64% 5% 11% 13% 7%	2918
June	1st to 10th	Day	69% 6% 8% 12% 5%	2700
	11th to 20th	Day	63% 5% 10% 16% 5%	2700
	21st to end	Day	59% 6% 12% 15% 7% 1	2700
July	1st to 10th	Day	54% 7% 14% 18% 6%	2625
	11th to 20th	Day	51% 8% 13% 21% 7%	2541
	21st to end	Day	57% 7% 14% 17% 4 1	2592
August	1st to 10th	Day	55% 6% 15% 20% 3	2492
	11th to 20th	Day	56% 6% 15% 16% 7%	2357
	21st to end	Day	53% 6% 15% 20% 6%	2534
September	1st to 10th	Day	51% 6% 12% 22% 9% 1	2160
	11th to 20th	Day	60% 6% 11% 17% 6%	2011
	21st to end	Day	53% 6% 16% 18% 8% 1	1980
October	1st to 10th	Day	53% 6% 12% 18% 9% 1	1948
	11th to 20th	Day	62% 6% 11% 16% 5%	1620
	21st to end	Day	66% 3 10% 15% 5% 1	1782
November	1st to 10th	Day	68% 7% 11% 10% 4 1	1670
	11th to 20th	Day	62% 5% 11% 14% 6% 1	1474
	21st to end	Day	66% 7% 10% 10% 7% 1	1330
December	1st to 10th	Day	71% 6% 11% 8% 4	1330
	11th to 20th	Day	72% 5% 11% 7% 5%	1667
	21st to end	Day	71% 4 9% 12% 3	2442
January	1st to 10th	Night	63% 4 8% 14% 8% 3	4694
	11th to 20th	Night	58% 12% 10% 14% 6%	4440
	21st to end	Night	63% 6% 10% 11% 9% 3	4884
February	1st to 10th	Night	66% 6% 10% 11% 7% 1	2660
	11th to 20th	Night	65% 6% 11% 12% 6%	2299
	21st to end	Night	56% 6% 10% 17% 11% 1	1776
March	1st to 10th	Night	62% 5% 8% 14% 9% 2	2160
	11th to 20th	Night	63% 5% 8% 15% 7% 1	2073
	21st to end	Night	63% 5% 7% 14% 10% 1	2044
April	1st to 10th	Night	66% 4 6% 13% 9% 1	1800
	11th to 20th	Night	62% 3 9% 17% 9% 1	1644
	21st to end	Night	63% 4 8% 15% 10%	1620
May	1st to 10th	Night	65% 5% 10% 15% 5% 1	1476
	11th to 20th	Night	62% 4 9% 17% 7% 1	1382
	21st to end	Night	61% 5% 10% 17% 7%	1357
June	1st to 10th	Night	68% 6% 11% 10% 5%	1260
	11th to 20th	Night	58% 6% 14% 16% 6%	1260
	21st to end	Night	59% 6% 11% 14% 8% 1	1260
July	1st to 10th	Night	50% 6% 18% 20% 6%	1226
	11th to 20th	Night	47% 6% 17% 22% 7% 1	1292
	21st to end	Night	57% 6% 14% 20% 4	1486
August	1st to 10th	Night	54% 8% 15% 19% 4	1422
	11th to 20th	Night	51% 7% 17% 18% 6%	1543
	21st to end	Night	47% 7% 18% 22% 6%	1819
September	1st to 10th	Night	48% 5% 14% 24% 9% 1	1800
	11th to 20th	Night	56% 5% 13% 17% 9% 1	1948
	21st to end	Night	50% 6% 15% 21% 7% 1	1980
October	1st to 10th	Night	55% 6% 12% 17% 9% 1	2009
	11th to 20th	Night	56% 6% 14% 17% 7% 1	2340
	21st to end	Night	61% 5% 11% 16% 6% 1	2574
November	1st to 10th	Night	63% 7% 11% 14% 6%	2408
	11th to 20th	Night	65% 6% 11% 14% 4	2706
	21st to end	Night	67% 6% 9% 11% 6%	2850
December	1st to 10th	Night	70% 7% 8% 11% 5%	2850
	11th to 20th	Night	74% 4 9% 9% 3	3533
	21st to end	Night	70% 5% 10% 12% 2	5225

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	26% 21% 32% 17% 4 1	370
	11th to 20th	Day	23% 22% 33% 17% 4 1	370
	21st to end	Day	25% 21% 31% 18% 4	407
February	1st to 10th	Day	25% 23% 31% 14% 6% 1	370
	11th to 20th	Day	26% 24% 35% 12% 1 1	348
	21st to end	Day	22% 22% 34% 15% 5% 3	280
March	1st to 10th	Day	23% 27% 32% 10% 7% 1	340
	11th to 20th	Day	28% 20% 26% 16% 8% 2	340
	21st to end	Day	29% 23% 27% 16% 4 1	434
April	1st to 10th	Day	32% 23% 28% 12% 3 1	420
	11th to 20th	Day	33% 15% 27% 19% 6% 1	544
	21st to end	Day	31% 19% 27% 17% 6% 1	600
May	1st to 10th	Day	41% 14% 20% 17% 5% 2	603
	11th to 20th	Day	31% 14% 26% 19% 8% 3	624
	21st to end	Day	33% 14% 33% 15% 4 1	680
June	1st to 10th	Day	38% 12% 23% 18% 7% 2	630
	11th to 20th	Day	37% 11% 24% 17% 9% 2	630
	21st to end	Day	26% 13% 30% 18% 10% 4	630
July	1st to 10th	Day	28% 13% 29% 19% 7% 4	620
	11th to 20th	Day	20% 12% 31% 25% 10% 1	618
	21st to end	Day	26% 11% 27% 26% 9%	685
August	1st to 10th	Day	26% 8% 29% 25% 10% 3	625
	11th to 20th	Day	23% 10% 25% 25% 13% 3	617
	21st to end	Day	23% 10% 30% 23% 12% 3	653
September	1st to 10th	Day	25% 15% 31% 19% 8% 1	450
	11th to 20th	Day	37% 16% 25% 17% 4 1	375
	21st to end	Day	22% 23% 34% 16% 5% 1	360
October	1st to 10th	Day	22% 22% 33% 17% 4 2	360
	11th to 20th	Day	33% 14% 25% 18% 7% 3	360
	21st to end	Day	30% 19% 28% 15% 8% 1	396
November	1st to 10th	Day	36% 22% 25% 12% 5% 1	365
	11th to 20th	Day	32% 20% 26% 15% 6% 1	370
	21st to end	Day	35% 21% 30% 11% 3	370
December	1st to 10th	Day	29% 19% 29% 16% 6% 1	370
	11th to 20th	Day	31% 23% 29% 13% 4	370
	21st to end	Day	27% 22% 29% 15% 5% 1	407
January	1st to 10th	Night	25% 21% 30% 18% 6% 1	850
	11th to 20th	Night	23% 23% 34% 16% 3	850
	21st to end	Night	23% 19% 36% 19% 2	935
February	1st to 10th	Night	25% 21% 32% 19% 4	850
	11th to 20th	Night	27% 21% 33% 15% 2 1	762
	21st to end	Night	20% 14% 37% 20% 7% 2	592
March	1st to 10th	Night	27% 21% 31% 16% 4 1	720
	11th to 20th	Night	22% 18% 30% 24% 6%	633
	21st to end	Night	31% 14% 33% 16% 5% 1	594
April	1st to 10th	Night	31% 20% 28% 16% 4 1	540
	11th to 20th	Night	28% 12% 31% 20% 6% 1	534
	21st to end	Night	33% 13% 29% 19% 5% 1	540
May	1st to 10th	Night	35% 10% 23% 23% 9% 1	540
	11th to 20th	Night	35% 9% 29% 17% 10%	532
	21st to end	Night	35% 11% 28% 20% 5% 1	583
June	1st to 10th	Night	38% 10% 21% 23% 7% 1	540
	11th to 20th	Night	33% 9% 24% 22% 11% 1	540
	21st to end	Night	31% 11% 28% 19% 10% 1	540
July	1st to 10th	Night	27% 10% 31% 24% 8% 1	526
	11th to 20th	Night	21% 9% 33% 30% 8%	522
	21st to end	Night	29% 6% 30% 27% 8%	590
August	1st to 10th	Night	25% 6% 26% 31% 10%	538
	11th to 20th	Night	29% 6% 27% 27% 11%	532
	21st to end	Night	23% 6% 29% 31% 10% 1	594
September	1st to 10th	Night	27% 9% 34% 24% 7%	540
	11th to 20th	Night	31% 13% 29% 22% 5%	540
	21st to end	Night	28% 13% 38% 16% 4 1	540
October	1st to 10th	Night	30% 11% 36% 18% 5% 1	567
	11th to 20th	Night	29% 12% 28% 22% 9% 1	810
	21st to end	Night	33% 14% 28% 19% 6%	891
November	1st to 10th	Night	30% 20% 30% 16% 4	830
	11th to 20th	Night	30% 18% 30% 16% 5% 1	850
	21st to end	Night	30% 22% 30% 16% 2	850
December	1st to 10th	Night	27% 19% 30% 18% 6%	850
	11th to 20th	Night	32% 19% 31% 14% 3	850
	21st to end	Night	24% 20% 31% 18% 6% 1	935

Page generated at 2024-02-12 07:35:31. Version ac07

Copyright 2024 Attilla Danko