West Jordan
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the West Jordan clear sky chart from 2005-11-06 to 2024-01-12.

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	6% 7% 3 5% 5% 3 4 5% 6% 7% 50%	74455
	Night	7% 7% 3 5% 5% 3 4 5% 5% 7% 49%	75236
Transparency	Day	33% 8% 11% 18% 19% 10%	74180
	Night	34% 7% 11% 19% 18% 10%	75032
Seeing	Day	10% 19% 33% 28% 8% 1	13697
	Night	10% 10% 24% 33% 19% 4	24327

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	13% 15% 4 7% 6% 2 5% 5% 5% 6% 32%	1708
	11th to 20th	Day	8% 14% 5% 8% 7% 3 5% 5% 6% 7% 32%	1629
	21st to end	Day	9% 15% 5% 8% 7% 4 5% 5% 5% 6% 31%	1782
February	1st to 10th	Day	9% 13% 5% 7% 6% 3 5% 5% 5% 6% 37%	1620
	11th to 20th	Day	9% 13% 5% 9% 6% 3 5% 4 5% 7% 35%	1646
	21st to end	Day	7% 13% 7% 9% 7% 3 5% 6% 5% 7% 32%	1480
March	1st to 10th	Day	5% 12% 5% 8% 5% 3 4 6% 6% 8% 39%	1919
	11th to 20th	Day	6% 9% 3 6% 5% 4 5% 6% 8% 9% 40%	1980
	21st to end	Day	9% 12% 4 8% 6% 4 6% 6% 6% 6% 33%	2178
April	1st to 10th	Day	10% 8% 4 6% 5% 4 5% 5% 6% 7% 42%	1991
	11th to 20th	Day	9% 10% 4 7% 5% 3 4 6% 5% 6% 42%	2276
	21st to end	Day	8% 8% 2 5% 5% 3 4 4 5% 8% 48%	2340
May	1st to 10th	Day	6% 5% 3 5% 5% 3 5% 6% 7% 9% 45%	2340
	11th to 20th	Day	6% 4 2 5% 4 3 4 6% 8% 10% 48%	2301
	21st to end	Day	6% 5% 2 5% 5% 4 6% 7% 8% 8% 44%	2530
June	1st to 10th	Day	3 3 2 4 4 3 4 5% 6% 10% 56%	2340
	11th to 20th	Day	5% 3 1 4 3 2 3 4 5% 6% 64%	2414
	21st to end	Day	2 2 1 2 3 2 3 4 4 6% 72%	2340
July	1st to 10th	Day	2 1 1 3 3 2 4 4 5% 8% 66%	2340
	11th to 20th	Day	4 3 1 3 4 2 4 5% 6% 8% 60%	2340
	21st to end	Day	3 2 1 4 4 3 6% 6% 7% 8% 56%	2545
August	1st to 10th	Day	3 2 1 4 4 3 5% 5% 6% 8% 59%	2328
	11th to 20th	Day	3 2 1 3 3 2 3 4 7% 7% 64%	2299
	21st to end	Day	3 3 1 4 4 2 4 5% 6% 7% 62%	2561
September	1st to 10th	Day	3 2 2 2 1 3 3 5% 6% 71%	2025
	11th to 20th	Day	4 2 2 2 3 3 4 4 5% 7% 65%	1980
	21st to end	Day	7% 2 1 2 3 2 2 2 4 6% 69%	1980
October	1st to 10th	Day	7% 5% 2 4 4 2 4 4 5% 6% 56%	1899
	11th to 20th	Day	7% 5% 2 4 4 2 3 3 4 7% 61%	1800
	21st to end	Day	6% 7% 2 3 3 3 3 4 5% 6% 57%	1969
November	1st to 10th	Day	8% 7% 2 5% 5% 3 5% 5% 5% 8% 48%	1674
	11th to 20th	Day	11% 8% 3 4 5% 2 3 4 4 7% 47%	1710
	21st to end	Day	7% 9% 4 6% 5% 3 4 4 5% 6% 46%	1599
December	1st to 10th	Day	9% 11% 5% 7% 4 3 4 4 5% 7% 42%	1520
	11th to 20th	Day	10% 11% 5% 8% 6% 4 5% 5% 6% 7% 32%	1926
	21st to end	Day	8% 13% 6% 9% 6% 3 4 4 5% 7% 35%	3146
January	1st to 10th	Night	13% 12% 4 7% 6% 3 4 5% 5% 8% 33%	2457
	11th to 20th	Night	10% 11% 4 7% 6% 4 6% 4 6% 7% 36%	2359
	21st to end	Night	8% 15% 4 7% 7% 4 6% 5% 6% 6% 33%	2574
February	1st to 10th	Night	9% 11% 4 7% 5% 3 5% 6% 5% 7% 38%	2340
	11th to 20th	Night	8% 12% 5% 6% 6% 3 5% 4 4 7% 41%	2199
	21st to end	Night	6% 12% 6% 8% 6% 3 3 5% 5% 8% 39%	1776
March	1st to 10th	Night	8% 13% 4 7% 5% 4 4 6% 6% 6% 37%	2039
	11th to 20th	Night	6% 9% 2 4 5% 3 5% 5% 7% 8% 45%	1980
	21st to end	Night	7% 11% 4 6% 6% 4 5% 5% 7% 7% 39%	2178
April	1st to 10th	Night	12% 10% 3 4 4 2 4 4 4 7% 47%	1967
	11th to 20th	Night	6% 7% 3 5% 6% 3 5% 6% 5% 7% 48%	1629
	21st to end	Night	10% 7% 3 4 4 3 5% 5% 5% 6% 50%	1620
May	1st to 10th	Night	7% 6% 3 4 5% 3 6% 6% 7% 8% 47%	1620
	11th to 20th	Night	7% 3 2 4 4 3 4 5% 7% 9% 52%	1594
	21st to end	Night	8% 4 2 4 4 3 5% 5% 6% 9% 50%	1746
June	1st to 10th	Night	5% 4 2 4 5% 2 4 5% 5% 8% 58%	1616
	11th to 20th	Night	4 3 1 3 3 3 2 3 4 7% 67%	1492
	21st to end	Night	2 3 1 3 3 1 2 4 6% 8% 68%	1620
July	1st to 10th	Night	2 2 1 4 5% 4 5% 5% 6% 8% 59%	1620
	11th to 20th	Night	3 3 2 4 5% 4 5% 5% 6% 8% 55%	1620
	21st to end	Night	3 3 2 5% 5% 3 4 5% 8% 10% 54%	1773
August	1st to 10th	Night	3 2 1 4 4 3 4 5% 5% 9% 59%	1611
	11th to 20th	Night	2 3 2 3 4 3 5% 6% 5% 6% 61%	1602
	21st to end	Night	2 2 1 4 4 3 3 5% 6% 7% 62%	1795
September	1st to 10th	Night	3 3 1 3 3 2 3 4 4 6% 69%	1933
	11th to 20th	Night	4 2 1 2 2 3 3 3 5% 7% 68%	1980
	21st to end	Night	6% 2 1 3 3 1 2 3 4 4 71%	1980
October	1st to 10th	Night	7% 4 2 3 3 2 4 4 4 7% 59%	2060
	11th to 20th	Night	7% 4 2 4 3 2 3 3 3 6% 63%	2160
	21st to end	Night	7% 6% 2 3 3 2 3 4 4 7% 60%	2384
November	1st to 10th	Night	8% 9% 2 4 4 2 4 4 5% 8% 51%	2405
	11th to 20th	Night	10% 6% 2 4 4 3 3 4 5% 9% 50%	2470
	21st to end	Night	8% 9% 3 5% 5% 2 3 5% 5% 6% 48%	2557
December	1st to 10th	Night	9% 10% 3 5% 5% 3 3 4 5% 7% 44%	2660
	11th to 20th	Night	13% 12% 5% 6% 5% 3 4 5% 5% 7% 37%	3271
	21st to end	Night	10% 12% 5% 9% 6% 4 5% 5% 5% 6% 34%	4549

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	52% 9% 16% 18% 4 1	1709
	11th to 20th	Day	52% 8% 13% 17% 8% 2	1629
	21st to end	Day	54% 10% 14% 13% 6% 2	1782
February	1st to 10th	Day	50% 9% 14% 16% 9% 1	1620
	11th to 20th	Day	48% 9% 13% 18% 11% 1	1655
	21st to end	Day	50% 10% 13% 17% 9% 1	1480
March	1st to 10th	Day	42% 12% 14% 21% 10% 2	1919
	11th to 20th	Day	39% 11% 14% 23% 12% 2	1980
	21st to end	Day	50% 11% 15% 15% 8% 2	2178
April	1st to 10th	Day	41% 10% 12% 17% 14% 5%	1991
	11th to 20th	Day	41% 9% 13% 20% 16% 2	2279
	21st to end	Day	35% 9% 12% 23% 20% 1	2340
May	1st to 10th	Day	32% 11% 11% 22% 20% 4	2340
	11th to 20th	Day	30% 9% 10% 24% 22% 5%	2304
	21st to end	Day	34% 11% 12% 23% 17% 3	2530
June	1st to 10th	Day	23% 8% 10% 21% 29% 9%	2340
	11th to 20th	Day	21% 6% 8% 18% 29% 19%	2414
	21st to end	Day	14% 4 6% 11% 31% 34%	2340
July	1st to 10th	Day	16% 6% 7% 12% 25% 35%	2276
	11th to 20th	Day	20% 7% 7% 11% 25% 29%	2271
	21st to end	Day	22% 8% 10% 12% 23% 26%	2404
August	1st to 10th	Day	22% 7% 9% 15% 22% 26%	2313
	11th to 20th	Day	17% 6% 8% 11% 31% 26%	2299
	21st to end	Day	20% 6% 7% 16% 31% 20%	2561
September	1st to 10th	Day	14% 6% 6% 15% 28% 29%	2025
	11th to 20th	Day	18% 8% 8% 18% 26% 22%	1980
	21st to end	Day	18% 5% 7% 20% 34% 16%	1980
October	1st to 10th	Day	29% 8% 8% 21% 26% 8%	1899
	11th to 20th	Day	25% 6% 9% 30% 25% 6%	1800
	21st to end	Day	28% 8% 14% 27% 21% 2	1969
November	1st to 10th	Day	35% 8% 14% 21% 18% 4	1674
	11th to 20th	Day	37% 8% 12% 28% 15% 1	1710
	21st to end	Day	41% 7% 13% 24% 14% 2	1599
December	1st to 10th	Day	44% 9% 17% 19% 9% 2	1520
	11th to 20th	Day	49% 9% 12% 19% 10%	1924
	21st to end	Day	46% 9% 15% 15% 14% 1	3146
January	1st to 10th	Night	50% 8% 15% 20% 6% 1	2457
	11th to 20th	Night	48% 8% 14% 17% 10% 2	2359
	21st to end	Night	50% 9% 15% 17% 7% 3	2574
February	1st to 10th	Night	46% 8% 16% 20% 9% 1	2340
	11th to 20th	Night	44% 7% 11% 20% 17% 2	2200
	21st to end	Night	43% 9% 13% 20% 13% 2	1776
March	1st to 10th	Night	47% 8% 10% 21% 13% 1	2039
	11th to 20th	Night	34% 10% 12% 25% 16% 2	1980
	21st to end	Night	42% 10% 14% 21% 10% 3	2178
April	1st to 10th	Night	38% 7% 13% 20% 16% 7%	1967
	11th to 20th	Night	33% 9% 12% 21% 21% 3	1629
	21st to end	Night	35% 8% 12% 21% 22% 2	1620
May	1st to 10th	Night	33% 10% 11% 22% 21% 3	1620
	11th to 20th	Night	26% 9% 11% 24% 22% 8%	1595
	21st to end	Night	30% 9% 14% 25% 18% 4	1746
June	1st to 10th	Night	25% 6% 9% 22% 28% 10%	1616
	11th to 20th	Night	18% 6% 9% 17% 28% 20%	1492
	21st to end	Night	16% 4 7% 9% 28% 36%	1620
July	1st to 10th	Night	22% 5% 8% 13% 17% 35%	1575
	11th to 20th	Night	26% 5% 7% 12% 19% 30%	1566
	21st to end	Night	24% 7% 10% 15% 18% 26%	1674
August	1st to 10th	Night	21% 7% 11% 14% 21% 26%	1602
	11th to 20th	Night	21% 6% 8% 11% 27% 27%	1602
	21st to end	Night	20% 6% 8% 12% 29% 25%	1795
September	1st to 10th	Night	18% 4 6% 15% 24% 33%	1933
	11th to 20th	Night	18% 4 8% 17% 27% 25%	1980
	21st to end	Night	19% 5% 5% 15% 33% 23%	1980
October	1st to 10th	Night	26% 6% 10% 20% 29% 9%	2060
	11th to 20th	Night	24% 6% 7% 26% 28% 9%	2160
	21st to end	Night	26% 7% 11% 24% 26% 5%	2384
November	1st to 10th	Night	33% 6% 11% 23% 21% 6%	2405
	11th to 20th	Night	32% 7% 14% 26% 18% 3	2470
	21st to end	Night	36% 7% 11% 26% 16% 4	2557
December	1st to 10th	Night	39% 9% 14% 24% 11% 3	2660
	11th to 20th	Night	46% 7% 13% 20% 12% 1	3272
	21st to end	Night	50% 8% 15% 14% 13% 1	4549

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% 19% 26% 21% 10%	270
	11th to 20th	Day	11% 23% 34% 21% 11% 2	243
	21st to end	Day	13% 22% 32% 22% 9% 1	264
February	1st to 10th	Day	14% 28% 34% 17% 7%	240
	11th to 20th	Day	14% 24% 36% 19% 6% 1	311
	21st to end	Day	14% 29% 37% 17% 3	346
March	1st to 10th	Day	14% 25% 37% 18% 5% 1	420
	11th to 20th	Day	12% 23% 40% 21% 5%	420
	21st to end	Day	18% 29% 35% 17% 1	462
April	1st to 10th	Day	15% 25% 31% 22% 5% 1	420
	11th to 20th	Day	18% 29% 31% 16% 6%	412
	21st to end	Day	15% 30% 24% 23% 6% 1	420
May	1st to 10th	Day	10% 27% 37% 19% 7% 1	423
	11th to 20th	Day	10% 23% 32% 25% 8% 2	448
	21st to end	Day	9% 19% 35% 25% 10% 2	485
June	1st to 10th	Day	4 18% 37% 32% 7% 3	450
	11th to 20th	Day	6% 21% 33% 27% 12% 1	524
	21st to end	Day	4 16% 38% 35% 6% 1	450
July	1st to 10th	Day	1 10% 37% 43% 8% 2	446
	11th to 20th	Day	4 9% 43% 34% 8% 2	444
	21st to end	Day	3 3 39% 41% 11% 2	487
August	1st to 10th	Day	5% 9% 37% 39% 9% 1	447
	11th to 20th	Day	3 9% 33% 42% 11% 3	437
	21st to end	Day	4 10% 33% 40% 10% 3	495
September	1st to 10th	Day	4 10% 34% 36% 14% 3	450
	11th to 20th	Day	5% 15% 32% 35% 10% 2	450
	21st to end	Day	8% 16% 25% 37% 13% 1	450
October	1st to 10th	Day	7% 24% 29% 27% 13%	369
	11th to 20th	Day	10% 18% 27% 29% 16% 1	270
	21st to end	Day	11% 20% 35% 26% 8%	297
November	1st to 10th	Day	17% 21% 26% 26% 8% 2	270
	11th to 20th	Day	13% 20% 34% 21% 10% 3	270
	21st to end	Day	15% 14% 28% 29% 12% 2	270
December	1st to 10th	Day	17% 16% 29% 26% 10% 2	270
	11th to 20th	Day	16% 18% 33% 26% 7%	270
	21st to end	Day	22% 21% 29% 25% 4	297
January	1st to 10th	Night	16% 11% 25% 28% 16% 4	760
	11th to 20th	Night	13% 11% 26% 30% 15% 5%	726
	21st to end	Night	15% 11% 22% 31% 17% 4	792
February	1st to 10th	Night	13% 10% 31% 30% 12% 3	720
	11th to 20th	Night	13% 11% 28% 32% 13% 3	704
	21st to end	Night	11% 15% 29% 30% 13% 2	592
March	1st to 10th	Night	13% 14% 30% 29% 10% 4	720
	11th to 20th	Night	10% 12% 26% 32% 17% 3	720
	21st to end	Night	12% 17% 27% 31% 10% 3	792
April	1st to 10th	Night	15% 15% 29% 28% 12% 2	707
	11th to 20th	Night	8% 15% 30% 33% 11% 2	533
	21st to end	Night	11% 11% 26% 33% 16% 3	540
May	1st to 10th	Night	8% 11% 31% 34% 14% 2	540
	11th to 20th	Night	7% 9% 24% 32% 23% 5%	531
	21st to end	Night	9% 10% 23% 32% 21% 4	584
June	1st to 10th	Night	5% 11% 22% 37% 22% 2	540
	11th to 20th	Night	5% 12% 25% 37% 19% 1	540
	21st to end	Night	3 6% 24% 37% 26% 4	540
July	1st to 10th	Night	2 6% 23% 34% 33% 2	525
	11th to 20th	Night	4 4 23% 43% 23% 3	522
	21st to end	Night	3 3 16% 36% 40% 2	591
August	1st to 10th	Night	4 3 22% 40% 28% 3	537
	11th to 20th	Night	3 3 17% 46% 27% 4	534
	21st to end	Night	3 5% 22% 42% 25% 4	594
September	1st to 10th	Night	5% 5% 18% 41% 26% 5%	673
	11th to 20th	Night	4 7% 18% 39% 24% 7%	720
	21st to end	Night	8% 6% 20% 30% 26% 10%	720
October	1st to 10th	Night	8% 9% 25% 34% 20% 5%	720
	11th to 20th	Night	8% 7% 23% 35% 22% 6%	720
	21st to end	Night	9% 10% 25% 30% 20% 5%	792
November	1st to 10th	Night	14% 11% 21% 29% 20% 4	740
	11th to 20th	Night	11% 11% 29% 29% 15% 5%	760
	21st to end	Night	12% 11% 23% 33% 16% 4	847
December	1st to 10th	Night	15% 11% 26% 32% 15% 1	950
	11th to 20th	Night	19% 10% 27% 31% 11% 2	950
	21st to end	Night	22% 13% 24% 31% 8% 1	851

Page generated at 2024-01-09 05:14:45. Version ac07

Copyright 2024 Attilla Danko