Weber County North Fork Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Weber County North Fork Park clear sky chart from 2005-11-06 to 2024-10-24.

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	7% 10% 3 6% 4 3 4 3 5% 6% 50%	101343
	Night	8% 10% 3 7% 4 3 4 3 4 6% 47%	97646
Transparency	Day	34% 5% 10% 18% 20% 13%	101106
	Night	37% 5% 11% 19% 18% 10%	97472
Seeing	Day	14% 13% 30% 28% 12% 3	15177
	Night	14% 6% 19% 37% 21% 3	25102

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	8% 21% 6% 11% 5% 3 4 3 3 5% 29%	2858
	11th to 20th	Day	9% 23% 8% 12% 5% 3 3 2 3 4 28%	2860
	21st to end	Day	8% 21% 7% 10% 4 3 3 3 3 5% 32%	3146
February	1st to 10th	Day	14% 19% 5% 9% 4 3 4 3 5% 5% 29%	1710
	11th to 20th	Day	10% 20% 5% 10% 6% 3 4 2 4 5% 31%	1721
	21st to end	Day	7% 20% 8% 13% 5% 4 4 3 5% 4 27%	1570
March	1st to 10th	Day	8% 22% 8% 9% 5% 3 4 2 3 5% 31%	3343
	11th to 20th	Day	6% 12% 4 7% 4 3 4 3 5% 5% 46%	3490
	21st to end	Day	13% 25% 6% 10% 5% 4 4 3 5% 5% 21%	3825
April	1st to 10th	Day	13% 13% 4 8% 5% 3 4 3 5% 6% 36%	2114
	11th to 20th	Day	11% 14% 3 8% 5% 4 4 3 5% 6% 39%	2417
	21st to end	Day	11% 12% 3 6% 4 3 3 3 6% 7% 41%	2470
May	1st to 10th	Day	9% 16% 3 7% 5% 4 4 4 5% 7% 36%	4110
	11th to 20th	Day	8% 5% 2 5% 3 3 4 3 6% 8% 54%	4071
	21st to end	Day	9% 6% 2 6% 4 4 5% 4 5% 7% 48%	4477
June	1st to 10th	Day	6% 5% 2 5% 4 4 4 4 6% 7% 54%	2646
	11th to 20th	Day	8% 4 2 4 3 3 3 3 5% 7% 58%	2690
	21st to end	Day	4 2 1 3 3 2 3 3 4 4 71%	2786
July	1st to 10th	Day	3 2 1 2 2 2 2 2 4 4 77%	4301
	11th to 20th	Day	3 2 1 3 2 3 3 3 6% 8% 65%	4110
	21st to end	Day	4 2 1 3 3 3 3 3 5% 7% 66%	4454
August	1st to 10th	Day	4 3 2 4 3 3 3 2 4 6% 66%	4092
	11th to 20th	Day	3 2 1 4 3 3 4 3 5% 5% 67%	4028
	21st to end	Day	3 2 1 2 2 2 3 3 4 5% 73%	4503
September	1st to 10th	Day	4 3 1 3 2 2 3 3 4 5% 70%	2152
	11th to 20th	Day	5% 3 1 5% 3 3 3 3 4 5% 64%	2090
	21st to end	Day	7% 4 1 3 3 2 2 3 4 4 67%	2090
October	1st to 10th	Day	12% 6% 2 5% 3 3 4 3 3 5% 54%	1995
	11th to 20th	Day	9% 6% 2 6% 3 3 3 3 5% 5% 56%	1900
	21st to end	Day	7% 8% 3 5% 3 3 3 3 4 6% 54%	1979
November	1st to 10th	Day	12% 12% 3 8% 3 4 3 4 5% 5% 42%	1674
	11th to 20th	Day	14% 11% 3 4 4 3 3 3 5% 7% 42%	1710
	21st to end	Day	9% 15% 5% 7% 3 3 4 3 5% 6% 40%	1525
December	1st to 10th	Day	11% 14% 5% 9% 6% 4 4 3 3 5% 36%	1520
	11th to 20th	Day	13% 15% 6% 10% 5% 4 4 4 5% 6% 28%	1926
	21st to end	Day	8% 14% 6% 10% 4 4 5% 3 6% 6% 34%	2990
January	1st to 10th	Night	8% 17% 7% 13% 5% 4 3 3 4 6% 32%	4097
	11th to 20th	Night	10% 24% 5% 12% 5% 3 4 3 4 4 26%	4110
	21st to end	Night	9% 21% 5% 9% 4 3 3 3 4 5% 32%	4521
February	1st to 10th	Night	12% 18% 4 9% 6% 3 4 4 4 5% 32%	2470
	11th to 20th	Night	11% 14% 4 9% 5% 3 4 3 4 5% 39%	2345
	21st to end	Night	6% 18% 5% 12% 5% 4 3 4 4 6% 33%	1884
March	1st to 10th	Night	13% 17% 5% 7% 4 4 4 4 4 4 33%	3529
	11th to 20th	Night	5% 9% 2 7% 4 4 3 3 6% 7% 48%	3490
	21st to end	Night	11% 18% 5% 9% 5% 4 5% 3 4 5% 32%	3828
April	1st to 10th	Night	12% 14% 3 6% 4 3 3 3 5% 5% 42%	2066
	11th to 20th	Night	10% 11% 4 7% 4 4 3 3 4 5% 44%	1708
	21st to end	Night	11% 9% 3 6% 4 4 4 3 5% 6% 47%	1710
May	1st to 10th	Night	12% 12% 3 6% 5% 4 5% 3 4 6% 39%	2860
	11th to 20th	Night	9% 3 2 4 3 3 3 3 5% 6% 59%	2834
	21st to end	Night	12% 5% 2 6% 5% 4 3 3 5% 6% 50%	3110
June	1st to 10th	Night	7% 4 2 5% 4 4 4 4 7% 7% 54%	1530
	11th to 20th	Night	8% 3 1 5% 3 3 3 3 5% 6% 61%	1479
	21st to end	Night	4 2 1 3 3 3 2 3 3 7% 69%	1386
July	1st to 10th	Night	3 2 1 3 2 2 3 2 4 4 74%	2656
	11th to 20th	Night	3 3 1 5% 4 3 4 4 5% 8% 59%	2860
	21st to end	Night	3 3 1 5% 3 3 4 4 5% 7% 61%	3109
August	1st to 10th	Night	4 3 1 5% 4 4 5% 3 5% 7% 60%	2847
	11th to 20th	Night	3 4 2 6% 4 4 4 3 5% 6% 60%	2811
	21st to end	Night	3 2 1 3 3 3 3 3 4 5% 70%	3163
September	1st to 10th	Night	5% 2 1 4 3 3 3 3 4 4 68%	2023
	11th to 20th	Night	7% 4 2 3 2 3 3 2 4 5% 65%	2090
	21st to end	Night	7% 3 1 3 2 2 2 2 3 4 70%	2090
October	1st to 10th	Night	10% 5% 2 4 3 3 3 3 4 5% 58%	2183
	11th to 20th	Night	10% 7% 2 4 3 2 3 3 4 5% 58%	2280
	21st to end	Night	8% 6% 2 5% 3 2 4 3 4 6% 57%	2438
November	1st to 10th	Night	12% 10% 2 5% 3 4 3 3 5% 6% 47%	2405
	11th to 20th	Night	11% 8% 2 6% 4 3 4 3 6% 7% 45%	2470
	21st to end	Night	8% 12% 3 7% 5% 4 4 3 4 5% 44%	2631
December	1st to 10th	Night	11% 13% 4 9% 5% 4 3 3 4 5% 38%	2660
	11th to 20th	Night	12% 13% 4 9% 5% 5% 5% 4 5% 6% 32%	3271
	21st to end	Night	9% 13% 6% 11% 5% 4 4 3 5% 6% 34%	4702

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	57% 7% 13% 18% 4 1	2859
	11th to 20th	Day	62% 6% 14% 13% 4 1	2860
	21st to end	Day	54% 8% 15% 16% 6% 1	3146
February	1st to 10th	Day	56% 6% 15% 14% 8% 1	1710
	11th to 20th	Day	54% 6% 13% 16% 9% 1	1730
	21st to end	Day	58% 6% 11% 16% 8% 1	1570
March	1st to 10th	Day	55% 5% 10% 19% 10% 1	3343
	11th to 20th	Day	36% 8% 10% 34% 12% 1	3490
	21st to end	Day	63% 7% 10% 15% 4 1	3825
April	1st to 10th	Day	47% 6% 12% 18% 12% 4	2114
	11th to 20th	Day	45% 7% 9% 21% 17% 2	2420
	21st to end	Day	41% 5% 11% 24% 18% 1	2470
May	1st to 10th	Day	42% 7% 11% 19% 17% 4	4110
	11th to 20th	Day	25% 5% 10% 30% 24% 6%	4074
	21st to end	Day	30% 7% 11% 24% 25% 2	4477
June	1st to 10th	Day	25% 6% 11% 23% 29% 6%	2646
	11th to 20th	Day	26% 4 7% 18% 28% 18%	2690
	21st to end	Day	16% 2 5% 12% 31% 34%	2786
July	1st to 10th	Day	12% 2 4 9% 14% 60%	4235
	11th to 20th	Day	15% 2 5% 9% 26% 42%	4041
	21st to end	Day	16% 3 6% 9% 31% 35%	4314
August	1st to 10th	Day	19% 2 6% 15% 29% 29%	4078
	11th to 20th	Day	18% 3 6% 14% 35% 24%	4067
	21st to end	Day	13% 3 5% 15% 36% 29%	4502
September	1st to 10th	Day	16% 3 7% 16% 30% 28%	2152
	11th to 20th	Day	21% 5% 8% 16% 33% 17%	2090
	21st to end	Day	20% 4 7% 21% 36% 12%	2090
October	1st to 10th	Day	33% 4 8% 22% 24% 9%	1995
	11th to 20th	Day	28% 5% 10% 29% 23% 5%	1900
	21st to end	Day	30% 5% 14% 29% 19% 2	1979
November	1st to 10th	Day	43% 6% 12% 20% 17% 1	1674
	11th to 20th	Day	40% 5% 16% 25% 14%	1710
	21st to end	Day	45% 5% 14% 22% 14% 1	1525
December	1st to 10th	Day	51% 7% 17% 15% 9% 2	1520
	11th to 20th	Day	55% 6% 14% 19% 5%	1924
	21st to end	Day	49% 6% 14% 19% 12% 1	2990
January	1st to 10th	Night	55% 6% 11% 21% 6% 1	4097
	11th to 20th	Night	62% 6% 14% 12% 5% 1	4110
	21st to end	Night	53% 8% 16% 17% 5% 2	4521
February	1st to 10th	Night	53% 7% 14% 19% 7%	2470
	11th to 20th	Night	47% 5% 11% 21% 15% 2	2346
	21st to end	Night	51% 6% 11% 21% 10% 2	1884
March	1st to 10th	Night	51% 5% 12% 19% 13% 1	3529
	11th to 20th	Night	33% 6% 12% 33% 14% 1	3490
	21st to end	Night	52% 6% 11% 23% 6% 1	3828
April	1st to 10th	Night	43% 5% 12% 21% 13% 5%	2066
	11th to 20th	Night	41% 6% 10% 22% 20% 2	1708
	21st to end	Night	37% 5% 11% 25% 20% 2	1710
May	1st to 10th	Night	42% 5% 12% 19% 19% 3	2860
	11th to 20th	Night	24% 5% 9% 29% 25% 7%	2835
	21st to end	Night	33% 5% 10% 23% 28% 1	3110
June	1st to 10th	Night	26% 6% 11% 21% 30% 6%	1530
	11th to 20th	Night	23% 3 7% 21% 29% 17%	1479
	21st to end	Night	17% 2 4 13% 29% 35%	1386
July	1st to 10th	Night	13% 2 5% 7% 15% 58%	2613
	11th to 20th	Night	22% 2 5% 8% 28% 34%	2806
	21st to end	Night	21% 3 6% 9% 28% 32%	3011
August	1st to 10th	Night	23% 3 6% 10% 29% 29%	2838
	11th to 20th	Night	25% 3 7% 13% 26% 26%	2838
	21st to end	Night	16% 3 6% 8% 29% 37%	3163
September	1st to 10th	Night	20% 3 6% 14% 24% 33%	2023
	11th to 20th	Night	22% 3 6% 16% 31% 22%	2090
	21st to end	Night	20% 3 6% 18% 36% 18%	2090
October	1st to 10th	Night	28% 3 8% 22% 29% 9%	2183
	11th to 20th	Night	29% 3 6% 30% 25% 6%	2280
	21st to end	Night	27% 5% 11% 32% 21% 4	2438
November	1st to 10th	Night	37% 5% 11% 24% 20% 4	2405
	11th to 20th	Night	37% 5% 14% 26% 16% 2	2470
	21st to end	Night	42% 4 12% 26% 13% 3	2631
December	1st to 10th	Night	47% 5% 16% 19% 9% 3	2660
	11th to 20th	Night	51% 7% 14% 20% 7%	3272
	21st to end	Night	50% 5% 16% 17% 12% 1	4702

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	27% 12% 24% 23% 12% 2	270
	11th to 20th	Day	18% 13% 31% 26% 11% 1	270
	21st to end	Day	15% 14% 26% 35% 7% 2	297
February	1st to 10th	Day	27% 15% 33% 20% 4 1	270
	11th to 20th	Day	20% 15% 39% 19% 6% 1	326
	21st to end	Day	18% 21% 38% 19% 4 1	382
March	1st to 10th	Day	22% 20% 30% 23% 5%	460
	11th to 20th	Day	17% 18% 33% 24% 7% 1	460
	21st to end	Day	28% 16% 36% 17% 3	506
April	1st to 10th	Day	20% 20% 31% 19% 9% 1	460
	11th to 20th	Day	22% 23% 31% 18% 5% 2	452
	21st to end	Day	20% 20% 28% 21% 9% 2	460
May	1st to 10th	Day	19% 19% 32% 21% 9%	463
	11th to 20th	Day	16% 16% 28% 27% 10% 2	488
	21st to end	Day	15% 13% 30% 24% 14% 3	529
June	1st to 10th	Day	5% 13% 26% 34% 17% 4	666
	11th to 20th	Day	12% 13% 30% 28% 15% 2	680
	21st to end	Day	6% 9% 34% 30% 18% 3	616
July	1st to 10th	Day	4 9% 37% 34% 12% 3	486
	11th to 20th	Day	4 6% 37% 36% 13% 4	484
	21st to end	Day	5% 4 33% 40% 15% 4	531
August	1st to 10th	Day	8% 6% 32% 34% 14% 5%	487
	11th to 20th	Day	5% 8% 28% 39% 14% 5%	477
	21st to end	Day	6% 8% 28% 37% 17% 5%	539
September	1st to 10th	Day	3 11% 28% 34% 17% 6%	490
	11th to 20th	Day	9% 12% 28% 32% 14% 5%	490
	21st to end	Day	9% 11% 29% 30% 18% 3	490
October	1st to 10th	Day	13% 12% 26% 27% 17% 5%	395
	11th to 20th	Day	11% 14% 27% 23% 21% 4	300
	21st to end	Day	14% 13% 32% 29% 11% 1	306
November	1st to 10th	Day	24% 14% 20% 26% 11% 5%	270
	11th to 20th	Day	15% 13% 29% 30% 10% 3	270
	21st to end	Day	15% 12% 21% 30% 19% 3	270
December	1st to 10th	Day	16% 11% 31% 25% 13% 5%	270
	11th to 20th	Day	21% 10% 30% 30% 7% 3	270
	21st to end	Day	26% 13% 27% 23% 8% 3	297
January	1st to 10th	Night	20% 6% 17% 35% 19% 3	760
	11th to 20th	Night	20% 6% 19% 36% 16% 3	760
	21st to end	Night	19% 6% 19% 36% 15% 4	836
February	1st to 10th	Night	21% 7% 24% 35% 11% 2	760
	11th to 20th	Night	15% 7% 27% 36% 14% 2	744
	21st to end	Night	12% 9% 30% 34% 14% 1	628
March	1st to 10th	Night	21% 8% 22% 35% 11% 3	760
	11th to 20th	Night	14% 7% 21% 40% 16% 2	760
	21st to end	Night	21% 9% 19% 35% 14% 1	836
April	1st to 10th	Night	20% 9% 22% 34% 14% 1	736
	11th to 20th	Night	15% 12% 24% 33% 14% 2	563
	21st to end	Night	17% 5% 19% 37% 18% 3	570
May	1st to 10th	Night	16% 8% 25% 32% 18% 1	570
	11th to 20th	Night	14% 5% 17% 33% 27% 3	561
	21st to end	Night	14% 6% 16% 36% 24% 4	617
June	1st to 10th	Night	9% 6% 16% 38% 29% 2	570
	11th to 20th	Night	10% 6% 22% 38% 22% 2	529
	21st to end	Night	6% 3 18% 37% 30% 5%	380
July	1st to 10th	Night	7% 4 14% 35% 35% 4	431
	11th to 20th	Night	7% 3 11% 44% 33% 2	552
	21st to end	Night	5% 1 7% 43% 40% 3	624
August	1st to 10th	Night	7% 2 11% 44% 35% 2	567
	11th to 20th	Night	4 1 14% 43% 36% 3	564
	21st to end	Night	7% 4 12% 39% 34% 5%	627
September	1st to 10th	Night	6% 4 12% 40% 34% 4	693
	11th to 20th	Night	9% 5% 12% 38% 28% 8%	760
	21st to end	Night	9% 5% 16% 32% 29% 9%	760
October	1st to 10th	Night	13% 6% 14% 38% 26% 4	760
	11th to 20th	Night	15% 4 15% 34% 28% 4	760
	21st to end	Night	12% 5% 18% 36% 25% 4	804
November	1st to 10th	Night	16% 6% 14% 38% 22% 4	740
	11th to 20th	Night	16% 4 20% 40% 16% 4	760
	21st to end	Night	14% 8% 20% 34% 20% 4	921
December	1st to 10th	Night	17% 7% 24% 37% 14% 1	950
	11th to 20th	Night	21% 8% 23% 34% 12% 2	950
	21st to end	Night	24% 8% 24% 32% 9% 2	939

Page generated at 2024-10-21 00:20:00. Version ac07

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