Estimate time with Your Hand

How can you estimate time remaining in case you forgot to take your watch and your mobile phone is out of battery?

Extend your arm fully and count the number of finger widths between the sun and the horizon. Each finger is about 15 minutes, which means each hand width should be about an hour. Remember that this is just an estimate, so if you want to be conservative, make sure to give yourself a bit more time than you measure if you want to get home before dark.

(according to Estimate the Time of Sunset with Your Hand)

How about estimating the current time?

According to Telling Time Using Only Your Hand you need to know the time of sunrise first but I found it works well even when I don't know the time of the sunrise since I am estimating and not finding the exact time. 

Look to the sun on horizon. If there are trees on the horizon, then use the tops of the trees as the horizon.Now hold your arm all the way out, palm side facing you like you're shading your eyes from the sun.

"Pinky" on the start of the horizon. From the bottom of your "Pinky" to the top of your "Pointer" finger,.. that's one hour!

So for example,

Starting at the horizon, lets say that it's three hand withs, stacked on top of each other, to the bottom of the sun...This means it's been light for 3 hours. If sunrise was at 6:00am, that would mean that it's now 9:15 or about 9:30. (Since I've never owned a Cell phone and never wear a watch, this has always been close enough for me.)

The bottom two fingers equals 30 minuets. 

Practise it and depending on whether you are in a jungle or in the city this trick can work as a life saver or an impressive trick.